I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

I think it's starved for gas.

Parts that come to mind are the electric choke, the idle screw, a bad
fuel-pump-like-device, or some obstruction in the fuel line.

The shop manual says adjusting the idle won't make much difference,
and come to think of it, it dies when the throttle is far above idle.

It starts so there must be enough choke then. How long would a
miniscooter take to fully warm and fully open the choke? A lot more
than 30 seconds, right? but to partially open? 15 seconds? Maybe
the choke never opens at all??? And that's why it dies. Then 10
minutes later the engine is totally cold again?

I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

Micky wrote:
I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

I think it's starved for gas.

Parts that come to mind are the electric choke, the idle screw, a bad
fuel-pump-like-device, or some obstruction in the fuel line.

The shop manual says adjusting the idle won't make much difference,
and come to think of it, it dies when the throttle is far above idle.

It starts so there must be enough choke then. How long would a
miniscooter take to fully warm and fully open the choke? A lot more
than 30 seconds, right? but to partially open? 15 seconds? Maybe
the choke never opens at all??? And that's why it dies. Then 10
minutes later the engine is totally cold again?

I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

You need to put back the 2" hose with the end cut at an angle .

--
Snag

Micky,


Does it die if you continue giving it squirts of ether?

Dave M.

On Thu, 26 Nov 2015 17:15:06 -0500, Micky
wrote:


I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

I think it's starved for gas.

Parts that come to mind are the electric choke, the idle screw, a bad
fuel-pump-like-device, or some obstruction in the fuel line.

The shop manual says adjusting the idle won't make much difference,
and come to think of it, it dies when the throttle is far above idle.

It starts so there must be enough choke then. How long would a
miniscooter take to fully warm and fully open the choke? A lot more
than 30 seconds, right? but to partially open? 15 seconds? Maybe
the choke never opens at all??? And that's why it dies. Then 10
minutes later the engine is totally cold again?

I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

Maybe you need to investigate that hose a little better. ;-)

On Thu, 26 Nov 2015 18:00:00 -0500, "David L. Martel"
wrote:

Micky,


Does it die if you continue giving it squirts of ether?

Dave M.

I can't keep squirting because I need to keep my left hand on the left
brake, and the air intake is just 8" offf the ground near the rear
axle, on the left side. If I kept my right hand on the right brake,
that would be even harder.

Now if I kept my right hand on the left brake.... no, my back will be
towards the scooter.

Maybe I'll get a friend to help.

On Thu, 26 Nov 2015 18:24:55 -0500, wrote:



I have to read about the fuel-pump-like-device.

Maybe you need to investigate that hose a little better. ;-)

The mystery hose. I put in my pocket, went out, and lost it. Unless
it's in some other pants. Probably not.

On 11/26/2015 03:15 PM, Micky wrote:
I have to read about the fuel-pump-like-device.

Fuel pump like device? I've only got a fuel pump on one bike and that's
because it's fuel injected. For the others the fuel system is stricktly
gravity fed. otoh my father refused to let me buy a Vespa when I was 16
since he thought any two wheeled vehicle with little bitty wheels was a
death trap. I've followed his advice although some of the new scooters
are sort of cute. Or at least the little red head I see on a pink
scooter every now and then.

On 11/26/2015 4:15 PM, Micky wrote:

I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

Almost certainly a fuel DELIVERY problem. I occasionally (which is why
I haven't torn it down or taken it to the shop to have it done) have a
very similar problem with a ZTR mower with a 22HP engine. Will start
right up then, within 15-20 seconds, will die off and won't start again.
Replaced the filter, then the fuel pump, all to no avail.

Finally, before calling for help, I pulled the fuel line from the output
of the fuel pump to the carb and tried blowing into it. No luck but I
wasn't sure if it was plugged or if I merely lacked the lung power to
get the job doneg

Grabbed a 60cc syringe with a catheter tip that fit nicely into the fuel
line and tried blowing INTO the carb. Again, no luck. Changed tactics
and tried sucking OUT from the carb and it worked. After doing so I
could pump into or suck out of the carb. Something in there blocking or
stuck. Reattached the fuel line to the pump, turned the key and I was
in business. Didn't have that problem for at least five or six weeks -
after a spell of temperature swings and little use. This time my first
step was to try and draw fuel from the carburetor and again I was
successful on the first try.

Give it a whirl; what do you have to lose?

On Thu, 26 Nov 2015 17:28:16 -0700, rbowman
wrote:

On 11/26/2015 03:15 PM, Micky wrote:
I have to read about the fuel-pump-like-device.

Fuel pump like device?

I'd read about in the manual but my memory could be better. Reading
again this evening, it's not a pump or even pump-like, but it is, what
did I call it in the other posts, a vacuum-controlled control valve.

How does that work? Vacuum at the base of the carburetor, where the
vacuum hose goes, turns the gas on or off?

I've only got a fuel pump on one bike and that's
because it's fuel injected. For the others the fuel system is stricktly
gravity fed. otoh my father refused to let me buy a Vespa when I was 16
since he thought any two wheeled vehicle with little bitty wheels was a
death trap. I've followed his advice although some of the new scooters
are sort of cute. Or at least the little red head I see on a pink
scooter every now and then.

Better than a pink head on a red scooter. If you have nothing that
isn't faster or slower than her scooter, maybe you could lie down on
the pavement as she approaches and look injured.

On Thu, 26 Nov 2015 17:28:16 -0700, rbowman
wrote:

On 11/26/2015 03:15 PM, Micky wrote:
I have to read about the fuel-pump-like-device.

Fuel pump like device? I've only got a fuel pump on one bike and that's
because it's fuel injected. For the others the fuel system is stricktly
gravity fed. otoh my father refused to let me buy a Vespa when I was 16
since he thought any two wheeled vehicle with little bitty wheels was a
death trap. I've followed his advice although some of the new scooters
are sort of cute. Or at least the little red head I see on a pink
scooter every now and then.
What kind of a scooter is this thing??? Nobady can give you an
intelligent answer without knowing what you are working on. Or even
if it's worth futzing with.

On Thursday, November 26, 2015 at 4:15:12 PM UTC-6, Micky wrote:
I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

Sounds like fuel starvation, look for a clogged fuel line. Blow it out with compressed air.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

I think it's starved for gas.

Parts that come to mind are the electric choke, the idle screw, a bad
fuel-pump-like-device, or some obstruction in the fuel line.

The shop manual says adjusting the idle won't make much difference,
and come to think of it, it dies when the throttle is far above idle.

It starts so there must be enough choke then. How long would a
miniscooter take to fully warm and fully open the choke? A lot more
than 30 seconds, right? but to partially open? 15 seconds? Maybe
the choke never opens at all??? And that's why it dies. Then 10
minutes later the engine is totally cold again?

I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

On Thu, 26 Nov 2015 19:04:46 -0600, Unquestionably Confused
wrote:

On 11/26/2015 4:15 PM, Micky wrote:

I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

Almost certainly a fuel DELIVERY problem. I occasionally (which is why
I haven't torn it down or taken it to the shop to have it done) have a
very similar problem with a ZTR mower with a 22HP engine. Will start
right up then, within 15-20 seconds, will die off and won't start again.
Replaced the filter, then the fuel pump, all to no avail.

Finally, before calling for help, I pulled the fuel line from the output
of the fuel pump to the carb and tried blowing into it. No luck but I
wasn't sure if it was plugged or if I merely lacked the lung power to
get the job doneg

Grabbed a 60cc syringe with a catheter tip that fit nicely into the fuel
line and tried blowing INTO the carb. Again, no luck. Changed tactics
and tried sucking OUT from the carb and it worked. After doing so I
could pump into or suck out of the carb. Something in there blocking or
stuck. Reattached the fuel line to the pump, turned the key and I was
in business. Didn't have that problem for at least five or six weeks -
after a spell of temperature swings and little use. This time my first
step was to try and draw fuel from the carburetor and again I was
successful on the first try.

Give it a whirl; what do you have to lose?

I'll give it a try.

I also went out in the dark and looked again for the fuel filter. It
wasn't in the tank, I'm glad to say, but it was hidden by a frame
member so I didn't see it. Only a little bigger than the last
section of my thumb.

So I'll try that too.

On Thu, 26 Nov 2015 17:15:06 -0500, Micky
wrote:

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

I think it's starved for gas.

Pull the air filter off and see it will run. It could be starving for
air / oxygen. Could be a dirty air filter.

Micky wrote:
I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

I haven't read all the posts related to this, but a few suggestions.

Can you put the scooter on a block so the rear wheel doesn't touch the ground
during testing?

The fuel pump like device, you said alsewhere, was an auto shut off valve. And
there was something about a missing 2" tube. Could the missing tube connect
vacuum from the carb to the valve to keep the fuel turned on? Replace the tube
and it may work. Any tube that was on it origionally is clearly necessary for
normal operation.

On 11/26/2015 10:28 PM, Micky wrote:
I also went out in the dark and looked again for the fuel filter. It
wasn't in the tank, I'm glad to say, but it was hidden by a frame
member so I didn't see it. Only a little bigger than the last
section of my thumb.

Some of those inline filters can lurk in the strangest places. Are you
getting clean gas out of the tank? A little rust can clog the filter in
short order.

On Fri, 27 Nov 2015 12:42:24 -0700, rbowman
wrote:

Some of those inline filters can lurk in the strangest places. Are you
getting clean gas out of the tank? A little rust can clog the filter in
short order.

That; plus, water in the tank. The clear plastic filters can show
crud from the tank. Shine a light in the tank and check. A turkey
baster can lift the water out. The tank, if it has rust can be
cleaned using electrolysis (set up at home).

On 11/27/2015 01:53 PM, Oren wrote:
The tank, if it has rust can be
cleaned using electrolysis (set up at home).

I've used phosphoric acid that you can find in the concrete section of
Home Depot or Lowe's. Phosphoric eats rust but not good metal and is
relative easy to handle. As an advantage, it leaves a phosphate coating
so the clean surface doesn't instantly rust like it will with
hydrochloric (muriatic) acid.

They sell specialized products but I've had good luck with the two part
pourable epoxy used for bar tops and decoupage to line the tank.

I got good at tank repair when I had a Yamaha Seca. The tank had low
points at the four corners where water collected and never left. To make
it worse, the bike had say for years.

On Fri, 27 Nov 2015 12:53:48 -0800, Oren wrote:

On Fri, 27 Nov 2015 12:42:24 -0700, rbowman
wrote:

Some of those inline filters can lurk in the strangest places. Are you
getting clean gas out of the tank? A little rust can clog the filter in
short order.

It's milky brown, but is that rust or too much water in the gas?
http://www.lcbamarketing.com/phase_s...hanol_blen.htm
Phase Separation in Ethanol Blended Gasoline’s

That; plus, water in the tank. The clear plastic filters can show
crud from the tank. Shine a light in the tank and check. A turkey
baster can lift the water out.

I used the turkey baster almost the first thing, well before I posted,
but I was only able to get 3 or 4 tablessppons out. Then I rolled
up newspaper and stuck that in the tank. That gets the liquid but I
don't think it gets solids if any like the turkey baster would if it
could. I tried the newspaper thing about 20 times, 10 pieces, 2 ends
each. At first I let it sit 2 or 3 minutes and it went 3 inches up
the paper, but I changed to 10 minutes and 6 inches up the paper, and
when I was all done, the gas level seemed about the same!!

The tank, if it has rust can be
cleaned using electrolysis (set up at home).

As to rust, I've the impression that the tank is plastic. Maybe not.
I'll check.

Also
http://www.postandcourier.com/articl...1602/305019925
Ethanol isn't a problem for automobiles because they are used almost
daily. It's an entirely different matter for boats, which often sit
unused for months at a time and have vented fuel systems that allow
moisture to enter the tanks. -- [I think this thing has a sealed
tank, but it might have sat for months unridden.]

"The biggest problem is ethanol is alcohol-based and alcohol absorbs
moisture from the atmosphere," Murphy explained. "Over a period of
months, it can add up to a half-gallon, maybe as much as a gallon of
water."

That water separates from the gas and sinks to the bottom of the fuel
tank. When a boat takes off, the bow rises and the fuel rushes to the
lowest spot in the tank, which is where the pickup tube is located.
Water is sucked into the engine, causing it to misfire.

On Fri, 27 Nov 2015 11:09:27 -0800, "Bob F"
wrote:

Micky wrote:
I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

I haven't read all the posts related to this, but a few suggestions.

Can you put the scooter on a block so the rear wheel doesn't touch the ground
during testing?

I could try that. Actually it has two kick stands and it's only using
the one that makes it lean. I hadn't tried too hard to get it up on
the two-legged kick stand because someone on the scooter webpage
thought that had to be not? deployed (whatever that means) to start
the bike. But a) the generic schematic doesn't show that, and b) now
that it starts easily (after a 10 minute wait ) I'll know if that's
true or not.

The fuel pump like device, you said alsewhere, was an auto shut off valve. And
there was something about a missing 2" tube. Could the missing tube connect
vacuum from the carb to the valve to keep the fuel turned on?

No, there's another tube that does that.

This tube it seems was meant to go nowhere. I found on google maps
in an industrial n'hood a place Nnnn Cycle Salvage, and when I went
there it was a dismal warehouse with almost no light, and only about
15 junk bikes afaict, but two were like mine and one still had a
carburetor, and it had the same 2" hose going nowhere. I don't get
it!

Replace the tube
and it may work. Any tube that was on it origionally is clearly necessary for
normal operation.

I did today, though I haven't put the 90 degree bend in it yet. That
might be necesssary too afaik.

I put my finger on the hole earlier and didn't feel blowing or
sucking.

It might be hard to feel sucking from such a little hole, but I also
put my finger on the hole where that tube to the auto-shut-off (vacuum
petcock) went, in the intake manifold, and I could feel a little
sucking there.

Earlier I had rolled up a tiny bit of newspaper and stuffed it in that
port, the vacuum porrt , and it ran no better or worse than when the
tube was on it. But when the engine stopped, after the usual 15
seconds or so, the piece of paper shot out 2 feet!!! ???????

Micky wrote:
On Fri, 27 Nov 2015 11:09:27 -0800, "Bob F"
wrote:

Micky wrote:
I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

I haven't read all the posts related to this, but a few suggestions.

Can you put the scooter on a block so the rear wheel doesn't touch
the ground during testing?

I could try that. Actually it has two kick stands and it's only using
the one that makes it lean. I hadn't tried too hard to get it up on
the two-legged kick stand because someone on the scooter webpage
thought that had to be not? deployed (whatever that means) to start
the bike. But a) the generic schematic doesn't show that, and b) now
that it starts easily (after a 10 minute wait ) I'll know if that's
true or not.

The fuel pump like device, you said alsewhere, was an auto shut off
valve. And there was something about a missing 2" tube. Could the
missing tube connect vacuum from the carb to the valve to keep the
fuel turned on?

No, there's another tube that does that.

This tube it seems was meant to go nowhere. I found on google maps
in an industrial n'hood a place Nnnn Cycle Salvage, and when I went
there it was a dismal warehouse with almost no light, and only about
15 junk bikes afaict, but two were like mine and one still had a
carburetor, and it had the same 2" hose going nowhere. I don't get
it!

Replace the tube
and it may work. Any tube that was on it origionally is clearly
necessary for normal operation.

I did today, though I haven't put the 90 degree bend in it yet. That
might be necesssary too afaik.

I put my finger on the hole earlier and didn't feel blowing or
sucking.

It might be hard to feel sucking from such a little hole, but I also
put my finger on the hole where that tube to the auto-shut-off (vacuum
petcock) went, in the intake manifold, and I could feel a little
sucking there.

Earlier I had rolled up a tiny bit of newspaper and stuffed it in that
port, the vacuum porrt , and it ran no better or worse than when the
tube was on it. But when the engine stopped, after the usual 15
seconds or so, the piece of paper shot out 2 feet!!! ???????

The vent tube is most likely a vent or overflow tube. The pointed end suggestewd
the later. The engine may have backfired as it died, pushing the paper out.

You clearly have a fuel problem. If it ran awhile before dieing, I'd suspect a
fuel tank vent was plugged. Your problem soundn more like a restricted fuel line
or obstructed float valve. Enough fuel gets through to gradually fill the float
bowl. Then it will start and run until the bowl getsa too low.

Do you get good flow of fuel when you disconnect the flue line from the carb? if
not, the line/filter/tank outlet probably is plugged some where. You could try
blowing it out backwards.

If the flow is good to the carb, then you need to clean out the carb float
valve. As you move the float up/down, it should clearly turn the fuel flow
off/on. You can test this using blown air instead of fuel for convenience.

http://www.repairfaq.org/sam/lmfaq.htm could be useful.

On Thu, 26 Nov 2015 19:04:46 -0600, Unquestionably Confused
wrote:

On 11/26/2015 4:15 PM, Micky wrote:

I was happy when I started to take the spark plug out and it was loose
I could do it with my fingers, but, after checking the gap, putting it
in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times now,
but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8 seconds
with the electric starter), if it's been 10 minutes or more since the
last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running fast,
it lopes along very slowly for another 10 seconds, instead of dying
more quickly. If I try to start it immediately after it's died, I
don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put it
on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good, 0.7mm,
and it sparks every time, when I electric crank it with the plug out
of the engine.

The owner's manual talks about not starting but not about starting and
dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

Almost certainly a fuel DELIVERY problem. I occasionally (which is why
I haven't torn it down or taken it to the shop to have it done) have a
very similar problem with a ZTR mower with a 22HP engine. Will start
right up then, within 15-20 seconds, will die off and won't start again.
Replaced the filter, then the fuel pump, all to no avail.

Finally, before calling for help, I pulled the fuel line from the output
of the fuel pump to the carb and tried blowing into it. No luck but I

OKay, I tried that today.

wasn't sure if it was plugged or if I merely lacked the lung power to
get the job doneg

I once blew hard to blow something up and I felt one of Eustachian
tubes swell in my head, or at least that's what it felt like. Scared
me, the thought of it bursting in my head. So I don't blow that hard
anymore.

Grabbed a 60cc syringe with a catheter tip

Okay, I didn't have 60 but I found a 20cc syringe, still in its
sealed, sterile, paper wrapper. I've had it in my junkbox for maybe
20 years, don't remember where I got it. This was the day I was
saving it for!!

that fit nicely into the fuel line

Well it was too small, but it had an opening-cover that was bigger so
I cut the tip off of that and put the hose on it.

and tried blowing INTO the carb. Again, no luck. Changed tactics

No luck.

and tried sucking OUT from the carb and it worked. After doing so I

Pulling slowly did nothing, so I quickly pulled the plunger straight
out of the rest of it. After 3 or 4 times, I saw a trace of something
in the hose. Did it 10 more times and the trace got longer,
eventually a bit of gas was coming out almost an inch, and then
receding again.

could pump into or suck out of the carb. Something in there blocking or
stuck. Reattached the fuel line to the pump, turned the key and I was
in business. Didn't have that problem for at least five or six weeks -
after a spell of temperature swings and little use. This time my first
step was to try and draw fuel from the carburetor and again I was
successful on the first try.

Give it a whirl; what do you have to lose?

So I was psyched, and when I started the scooter right afterwards, it
seemed to run faster (with more throttle) and a longer, but it was
only a few seconds longer at most and then it loped and then it
stalled.

Debated whether to drain the tank and buy a gallon of hi-test, and
then it started to rain, earlier than predicted. It's going to be
colder or rainy for a week.

The milky brown gas is probably water in the gas. Maybe the top layer
is gasoline and it floats, but after 30 seconds it uses that and the
rest comes from the bottom of the tank which has more water, then
after 10 munutes somehow there is gasoline in the bowl t hat floats to
the top of the bowl and it works again. Makes no sense.

But I think I have to drain the tank, remove the carb and turn it
upsided down to pour everything out.

Unless there's some way I could empty the bowl without removing the
carb? Blowing air through it from a little compressor? How long
would that take?


(One poster said he couldn't take the carb apart without drilling out
the rivets.)

Micky wrote:
On Thu, 26 Nov 2015 19:04:46 -0600, Unquestionably Confused
wrote:

On 11/26/2015 4:15 PM, Micky wrote:

I was happy when I started to take the spark plug out and it was
loose I could do it with my fingers, but, after checking the gap,
putting it in tight didn't make it start any better.

Still, the engine on the 50cc motorscooter has started many times
now, but it never runs more than 30 or 45 seconds.

It starts even if no ether is used, often fairly quickly (5-8
seconds with the electric starter), if it's been 10 minutes or more
since the last time I ran it or tried to run it.

But after 15 seconds it dies.

It runs pretty fast if I give it a lot of throttle, but it still
starts to die within 15 seconds. Sometimes if I had it running
fast, it lopes along very slowly for another 10 seconds, instead of
dying more quickly. If I try to start it immediately after it's
died, I don't think it's ever started then.

Removing the gas cap didn't help (it wasn't on tight in the first
place because I have no key and have to use a screwdriver if I put
it on tight. And I'm sure it's not air-tight even when perfect.)

It couldn't be bad gas or it wouldn't start at all.

I've removed the spark plug and the gap turned oout to be good,
0.7mm, and it sparks every time, when I electric crank it with the
plug out of the engine.

The owner's manual talks about not starting but not about starting
and dying. I'll go look at the manual

I think it's a fuel problem. It's certainly not compression and I'm
99% sure it's not spark.

Almost certainly a fuel DELIVERY problem. I occasionally (which is
why I haven't torn it down or taken it to the shop to have it done)
have a very similar problem with a ZTR mower with a 22HP engine.
Will start right up then, within 15-20 seconds, will die off and
won't start again. Replaced the filter, then the fuel pump, all to
no avail.

Finally, before calling for help, I pulled the fuel line from the
output of the fuel pump to the carb and tried blowing into it. No
luck but I

OKay, I tried that today.

wasn't sure if it was plugged or if I merely lacked the lung power to
get the job doneg

I once blew hard to blow something up and I felt one of Eustachian
tubes swell in my head, or at least that's what it felt like. Scared
me, the thought of it bursting in my head. So I don't blow that hard
anymore.

Grabbed a 60cc syringe with a catheter tip

Okay, I didn't have 60 but I found a 20cc syringe, still in its
sealed, sterile, paper wrapper. I've had it in my junkbox for maybe
20 years, don't remember where I got it. This was the day I was
saving it for!!

that fit nicely into the fuel line

Well it was too small, but it had an opening-cover that was bigger so
I cut the tip off of that and put the hose on it.

and tried blowing INTO the carb. Again, no luck. Changed tactics

No luck.

and tried sucking OUT from the carb and it worked. After doing so I

Pulling slowly did nothing, so I quickly pulled the plunger straight
out of the rest of it. After 3 or 4 times, I saw a trace of something
in the hose. Did it 10 more times and the trace got longer,
eventually a bit of gas was coming out almost an inch, and then
receding again.

could pump into or suck out of the carb. Something in there
blocking or stuck. Reattached the fuel line to the pump, turned the
key and I was in business. Didn't have that problem for at least
five or six weeks - after a spell of temperature swings and little
use. This time my first step was to try and draw fuel from the
carburetor and again I was successful on the first try.

Give it a whirl; what do you have to lose?

So I was psyched, and when I started the scooter right afterwards, it
seemed to run faster (with more throttle) and a longer, but it was
only a few seconds longer at most and then it loped and then it
stalled.

Debated whether to drain the tank and buy a gallon of hi-test, and
then it started to rain, earlier than predicted. It's going to be
colder or rainy for a week.

The milky brown gas is probably water in the gas. Maybe the top layer
is gasoline and it floats, but after 30 seconds it uses that and the
rest comes from the bottom of the tank which has more water, then
after 10 munutes somehow there is gasoline in the bowl t hat floats to
the top of the bowl and it works again. Makes no sense.

But I think I have to drain the tank, remove the carb and turn it
upsided down to pour everything out.

Unless there's some way I could empty the bowl without removing the
carb? Blowing air through it from a little compressor? How long
would that take?


(One poster said he couldn't take the carb apart without drilling out
the rivets.)

Any gas that is cloudy, green, or dirty looking ought to have been disposed of
from day 1.
Trying to fix an engine full of bad gas is a waste of time.

Chances are the carb is cruded up and jets may be plugged and the float valve is
very likely plugged. Just blowing air into the carb may pop out metal plugs
internally that can be removed to clean passages, but you want to do it
carefully so you know where the plugs go. The plugs I've seen were round dome
shaped sheet metal.

Do you get good gas flow out of the fuel lie when disconnected from the carb?

On 11/29/2015 01:20 AM, Micky wrote:
Unless there's some way I could empty the bowl without removing the
carb? Blowing air through it from a little compressor? How long
would that take?

A lot of motorcycle carbs have a screw to drain the float bowl. I'm not
a big believer in snake oil but I've had good luck with Sea Foam for
cleaning up carbs without disassembling them as long as the engine runs
enough to pull it through.

On Sat, 28 Nov 2015 09:55:18 -0800, "Bob F"
wrote:

Micky wrote:
On Fri, 27 Nov 2015 11:09:27 -0800, "Bob F"
wrote:

Micky wrote:
I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

I haven't read all the posts related to this, but a few suggestions.

Can you put the scooter on a block so the rear wheel doesn't touch
the ground during testing?

I could try that. Actually it has two kick stands and it's only using
the one that makes it lean. I hadn't tried too hard to get it up on
the two-legged kick stand because someone on the scooter webpage
thought that had to be not? deployed (whatever that means) to start
the bike. But a) the generic schematic doesn't show that, and b) now
that it starts easily (after a 10 minute wait ) I'll know if that's
true or not.

The fuel pump like device, you said alsewhere, was an auto shut off
valve. And there was something about a missing 2" tube. Could the
missing tube connect vacuum from the carb to the valve to keep the
fuel turned on?

No, there's another tube that does that.

This tube it seems was meant to go nowhere. I found on google maps
in an industrial n'hood a place Nnnn Cycle Salvage, and when I went
there it was a dismal warehouse with almost no light, and only about
15 junk bikes afaict, but two were like mine and one still had a
carburetor, and it had the same 2" hose going nowhere. I don't get
it!

Replace the tube
and it may work. Any tube that was on it origionally is clearly
necessary for normal operation.

I did today, though I haven't put the 90 degree bend in it yet. That
might be necesssary too afaik.

I put my finger on the hole earlier and didn't feel blowing or
sucking.

It might be hard to feel sucking from such a little hole, but I also
put my finger on the hole where that tube to the auto-shut-off (vacuum
petcock) went, in the intake manifold, and I could feel a little
sucking there.

Earlier I had rolled up a tiny bit of newspaper and stuffed it in that
port, the vacuum porrt , and it ran no better or worse than when the
tube was on it. But when the engine stopped, after the usual 15
seconds or so, the piece of paper shot out 2 feet!!! ???????

The vent tube is most likely a vent or overflow tube. The pointed end suggestewd
the later. The engine may have backfired as it died, pushing the paper out.

You clearly have a fuel problem. If it ran awhile before dieing, I'd suspect a
fuel tank vent was plugged. Your problem soundn more like a restricted fuel line
or obstructed float valve. Enough fuel gets through to gradually fill the float
bowl. Then it will start and run until the bowl getsa too low.

Do you get good flow of fuel when you disconnect the flue line from the carb? if

It seems good to me. It's not as great as what comes from the hose
directly connected to the tank, buit it has to pass through the
filter, the vacuum petcock and three other short hoses. When I suck
on the petcock vacuum it turns on and when I stop sucking, it stops or
lets a trickle through.

I figured maybe I thought I was sucking for 15 seconds but had really
stopped, so when the engine slowed down, I sucked harder. No change,
still slowing down and dying.

not, the line/filter/tank outlet probably is plugged some where. You could try
blowing it out backwards.

If the flow is good to the carb, then you need to clean out the carb float
valve. As you move the float up/down, it should clearly turn the fuel flow
off/on. You can test this using blown air instead of fuel for convenience.

I blew with my lungs but nothing happened. What about an air
compressor?


http://www.repairfaq.org/sam/lmfaq.htm could be useful.

On Sun, 29 Nov 2015 12:35:35 -0700, rbowman
wrote:

On 11/29/2015 01:20 AM, Micky wrote:
Unless there's some way I could empty the bowl without removing the
carb? Blowing air through it from a little compressor? How long
would that take?

A lot of motorcycle carbs have a screw to drain the float bowl. I'm not
a big believer in snake oil but I've had good luck with Sea Foam for
cleaning up carbs without disassembling them as long as the engine runs
enough to pull it through.

Well, at 15 seconds a pop, how many times do I have to run it to use
the same amount that is in the bowl? And how many times do I have to
run it to actually flush out the bowl? I know, the second question is
much harder to answer.

Still I'm not sure how hard it is to take off the carb so the sea
foam might be worth it. I think there is a drain screw but I dont'
think I can get at it without removing the carb. I know that's not
the carb designer's plan but it's worked out that way. I can't feel
it or see it or see it with a dental mirror. I can only see it when
I look at what I think is the same carb in Amazon

http://www.amazon.com/50cc-18mm-Carb...B004J5CJVA#Ask
The top picture enlarged. Clearly shows the screw. Don't be confused
by the grey hose, which is actually behind the screw, and just happens
to be in that position, not connected to anything. I guess they
include a llittle piece of hose, as well as a fuel filter. The whole
carb is upside down in this picture.


The bottom picture, enlarged shows the strange short tube, which comes
from somewhere much higher. In this picture, the bottom of the carb
is on the bottom of the screen and the output is in the middle of the
screen.

But it will probably have to wait until the spring.

On 11/29/2015 03:14 PM, Micky wrote:
The bottom picture, enlarged shows the strange short tube, which comes
from somewhere much higher. In this picture, the bottom of the carb
is on the bottom of the screen and the output is in the middle of the
screen.


https://www.youtube.com/watch?v=SCcdaTjuIL4

I don't know if you've found that video and if it's the same carb but it
looks like the sort of armored tube is the drain and there is a screw at
the bottom of it?

Couple of relevant comments but no real answers. Electric choke?

On Sun, 29 Nov 2015 21:19:49 -0700, rbowman
wrote:

On 11/29/2015 03:14 PM, Micky wrote:
The bottom picture, enlarged shows the strange short tube, which comes
from somewhere much higher. In this picture, the bottom of the carb
is on the bottom of the screen and the output is in the middle of the
screen.


https://www.youtube.com/watch?v=SCcdaTjuIL4

I'll look next. ....., Wow, an excellent video for me Thanks a lot.

I had tried to open the air cleaner cover but even in the daytime, the
sky was too cloudy and dark to find the last screw. Should have gotten
a flashlight, but it's soft plastic and I pulled it open enough to
pull out the foam air cleaner a little bit. Looked like new and
clean. And I left it pulled out a bit so no interference with air
intake for a few tries.

I'm 99.9% sure this carb has no drain *hose*, but it almost surely has
that drain, so maybe I won't have to open the carb, maybe I just have
to clean it out.

It's also a good video becaus it lists eveyrthing I have to do to get
the carb off.

IS IT A BAD IDEA TO REMOVE THE CARB, LEAVE THE INTAKE MANIFOLD OPEN,
EXCEPT FOR A RAG STUFFED IN IT, and the hoses open because they're not
connected, FOR THE REST OF THE WINTER, UNTIL APRIL? Maybe I think I
can do everything in one day and then I can't and it drags on to
April. Why does cold weather seem like it would hurt the inside of
the engine more than warm weather, when chemical reactions are faster
when it's warm?

When I lived in Brooklyn NY 30 years ago, there was always one weekend
day each month in the winter warm enough to put the top down and go
for a drive. Now I have 7 days to work with but I don't remember
always getting warm days in the winter in Baltimore. It's not that
I can't work in the cool or cold -- I can and do when it's important
-- but that this is meant to be fun, and it's not so much fun if I'm
cold. And I'm not going to ride it, for fun, unless the weather is
warm.

As to reassembly, after I had already decided to check the petcock by
sucking on it, I read a review that seemed to say it was part of
assembly instructions to suck on it, though other reviews said there
were no assembly instructions!! I think there really are.

I don't know if you've found that video and if it's the same carb but it
looks like the sort of armored tube is the drain and there is a screw at
the bottom of it?

Couple of relevant comments but no real answers. Electric choke?

Yes, it has that. I can imagine the choke causing problems. I wanted
to look at it, or control it manaually. It's attached with two
Phillips screws I felt I wasn't getting a good bite on one screw and
the full-size screwdriver I had with me wouldn't fit the other. I
meant to come back with a smaller one. And I was trying to figure
out how not to lose the washers that someone said it had.

OTOH, I can't imagine it getting that warm in 15 seconds that would
cause too much choke to be a problem. And if too much choke were
the problem, I can't imagine it running 15 whole seconds. There
isn't much change in choke position in beteen the 3rd second and the
15th second in my experience with cars.

On 11/29/2015 11:28 PM, Micky wrote:
IS IT A BAD IDEA TO REMOVE THE CARB, LEAVE THE INTAKE MANIFOLD OPEN,
EXCEPT FOR A RAG STUFFED IN IT, and the hoses open because they're not
connected, FOR THE REST OF THE WINTER, UNTIL APRIL?

You should be okay. I've used a piece of duct tape over engine openings
I wanted to cover too. A little acetone takes the goo off if there is
any when you remove it.

Micky wrote:
On Sat, 28 Nov 2015 09:55:18 -0800, "Bob F"
wrote:

Micky wrote:
On Fri, 27 Nov 2015 11:09:27 -0800, "Bob F"
wrote:

Micky wrote:
I tried to take off the fuel line to see how much comes out, but I
didn't have the right tool. And now it's dark out. Tomorrow
should be warm too.

I have to read about the fuel-pump-like-device.

I haven't read all the posts related to this, but a few
suggestions.

Can you put the scooter on a block so the rear wheel doesn't touch
the ground during testing?

I could try that. Actually it has two kick stands and it's only
using the one that makes it lean. I hadn't tried too hard to get
it up on the two-legged kick stand because someone on the scooter
webpage thought that had to be not? deployed (whatever that means)
to start the bike. But a) the generic schematic doesn't show that,
and b) now that it starts easily (after a 10 minute wait ) I'll
know if that's true or not.

The fuel pump like device, you said alsewhere, was an auto shut off
valve. And there was something about a missing 2" tube. Could the
missing tube connect vacuum from the carb to the valve to keep the
fuel turned on?

No, there's another tube that does that.

This tube it seems was meant to go nowhere. I found on google maps
in an industrial n'hood a place Nnnn Cycle Salvage, and when I went
there it was a dismal warehouse with almost no light, and only about
15 junk bikes afaict, but two were like mine and one still had a
carburetor, and it had the same 2" hose going nowhere. I don't get
it!

Replace the tube
and it may work. Any tube that was on it origionally is clearly
necessary for normal operation.

I did today, though I haven't put the 90 degree bend in it yet.
That might be necesssary too afaik.

I put my finger on the hole earlier and didn't feel blowing or
sucking.

It might be hard to feel sucking from such a little hole, but I also
put my finger on the hole where that tube to the auto-shut-off
(vacuum petcock) went, in the intake manifold, and I could feel a
little sucking there.

Earlier I had rolled up a tiny bit of newspaper and stuffed it in
that port, the vacuum porrt , and it ran no better or worse than
when the tube was on it. But when the engine stopped, after the
usual 15 seconds or so, the piece of paper shot out 2 feet!!!
???????

The vent tube is most likely a vent or overflow tube. The pointed
end suggestewd the later. The engine may have backfired as it died,
pushing the paper out.

You clearly have a fuel problem. If it ran awhile before dieing, I'd
suspect a fuel tank vent was plugged. Your problem soundn more like
a restricted fuel line or obstructed float valve. Enough fuel gets
through to gradually fill the float bowl. Then it will start and run
until the bowl getsa too low.

Do you get good flow of fuel when you disconnect the flue line from
the carb? if

It seems good to me. It's not as great as what comes from the hose
directly connected to the tank, buit it has to pass through the
filter, the vacuum petcock and three other short hoses. When I suck
on the petcock vacuum it turns on and when I stop sucking, it stops or
lets a trickle through.

I figured maybe I thought I was sucking for 15 seconds but had really
stopped, so when the engine slowed down, I sucked harder. No change,
still slowing down and dying.

not, the line/filter/tank outlet probably is plugged some where. You
could try blowing it out backwards.

If the flow is good to the carb, then you need to clean out the carb
float valve. As you move the float up/down, it should clearly turn
the fuel flow off/on. You can test this using blown air instead of
fuel for convenience.

I blew with my lungs but nothing happened. What about an air
compressor?

If you blew into the fuel intake and didn't get air flow to turn on/off as you
move the float down/up, then the main fuel passage to the float is plugged
somewhere. This all assumes you accessed the float to do the test. If not:

Did you try blowing after running the carb dry. At that time, the float should
be opening, and some air should flow. Opening the drain to the float bowl should
make that more obvious.

Beware - blowing into carb passages with an air compressor can pop out necessary
plugs that block off some passages.

On Mon, 30 Nov 2015 09:57:56 -0800, "Bob F"
wrote:

Micky wrote:
On Sat, 28 Nov 2015 09:55:18 -0800, "Bob F"
wrote:
...................
The vent tube is most likely a vent or overflow tube. The pointed
end suggestewd the later. The engine may have backfired as it died,
pushing the paper out.

You clearly have a fuel problem. If it ran awhile before dieing, I'd
suspect a fuel tank vent was plugged. Your problem soundn more like
a restricted fuel line or obstructed float valve. Enough fuel gets
through to gradually fill the float bowl. Then it will start and run
until the bowl getsa too low.

Do you get good flow of fuel when you disconnect the flue line from
the carb? if

It seems good to me. It's not as great as what comes from the hose
directly connected to the tank, buit it has to pass through the
filter, the vacuum petcock and three other short hoses. When I suck
on the petcock vacuum it turns on and when I stop sucking, it stops or
lets a trickle through.

I figured maybe I thought I was sucking for 15 seconds but had really
stopped, so when the engine slowed down, I sucked harder. No change,
still slowing down and dying.

not, the line/filter/tank outlet probably is plugged some where. You
could try blowing it out backwards.

If the flow is good to the carb, then you need to clean out the carb
float valve. As you move the float up/down, it should clearly turn
the fuel flow off/on. You can test this using blown air instead of
fuel for convenience.

I blew with my lungs but nothing happened. What about an air
compressor?

If you blew into the fuel intake and didn't get air flow to turn on/off as you
move the float down/up,

How would I move the float up and down? The carb is still in one
piece, and mounted in one place.

then the main fuel passage to the float is plugged
somewhere. This all assumes you accessed the float to do the test. If not:

Did you try blowing after running the carb dry.

That's a good idea. I don't know that I've ever run it dry, but I've
run it to the point where it stops.

At that time, the float should
be opening, and some air should flow. Opening the drain to the float bowl should
make that more obvious.

I can't get at that without removing the carb.

Beware - blowing into carb passages with an air compressor can pop out necessary
plugs that block off some passages.

The output pressure is adjustable. I'll be careful.