(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules

Jules Richardson wrote:
....

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? ...

Does it have a fuel filter? What position is the choke plate in; is it
functioning correctly?

How did it run last year? You say it's old, is the carb body worn badly
at the throttle plate shaft holes so the air mixture is fouled up
badly--that's a typical failure mechanism with age. It tends to make
them run w/ a noticeable surge as the air:fuel mixture varies widely as
a symptom from last year did it have such behavior?

As another posted, perhaps there is some small sediment impeding the
carb or the float is stuck or similar problem. Does it seem starved or
rich for fuel-related symptoms?

What shape is the plug? What about the plug wire; is it in good
condition or could it be cracked from age?

Oh, so many choices...

--

On Apr 30, 9:42*am, dpb wrote:
Jules Richardson wrote:

...

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? ...

Does it have a fuel filter? *What position is the choke plate in; is it
functioning correctly?

How did it run last year? *You say it's old, is the carb body worn badly
at the throttle plate shaft holes so the air mixture is fouled up
badly--that's a typical failure mechanism with age. *It tends to make
them run w/ a noticeable surge as the air:fuel mixture varies widely as
a symptom from last year did it have such behavior?

As another posted, perhaps there is some small sediment impeding the
carb or the float is stuck or similar problem. *Does it seem starved or
rich for fuel-related symptoms?

What shape is the plug? *What about the plug wire; is it in good
condition or could it be cracked from age?

Oh, so many choices... *

--

I agree with some of the others.

Have you cranked it with the plug out and connected? Do this in the
shade. Remove the plug, Hook it back to the plug wire. Lay it on
the cylinder head or block somewhere where it is grounded. Crank it.
You see sparks? If not you have an ignition issue.

With it all assembled remove the air cleaner. Spray a little starter
fluid into the carb while cranking it. If it fires and tries to run
but then dies you have a gas delivery issue. Disconnect the fuel line
and see if gas runs out all over the place. If it doesn;t then blow
into the line and if that causes gas to start running out you have
crud in your tank. If the gas line is not clogged then you have carb
problem.

If you have spark and it won't even try to start while spraying
starter fluid into it then check the shear pin under the flywheel.

See if it will run for a second or two on ether, sprayed
onto the air filter. Warning.... do not spray ether directly
into the air intake. Double definitely not into the spark
plug hole. (That's how my Dad's generator got killed.) If
so, you've got carb problems.

Other thing to do, is to remove the carb, and put some
Permatex #2 non hardening on both sides of the gasket. They
dry out, and then the engine sucks air through the gasket,
instead of drawing gas mix.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


wrote in message
...

If it ran when you parked it for the winter, and it doesn't
run now,
then it is almost a 100% certainty that your carb is not as
clean as
you think. It needs to be disassembled, soaked in proper
carb cleaner,
and all the passages blown clear with compressed air.

Then start over with a dry, clean, gas tank and lines. Fill
with gas
that you bought within the past month.

On Apr 30, 9:42�am, dpb wrote:
Jules Richardson wrote:

...

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? ...

Does it have a fuel filter? �What position is the choke plate in; is it
functioning correctly?

How did it run last year? �You say it's old, is the carb body worn badly
at the throttle plate shaft holes so the air mixture is fouled up
badly--that's a typical failure mechanism with age. �It tends to make
them run w/ a noticeable surge as the air:fuel mixture varies widely as
a symptom from last year did it have such behavior?

As another posted, perhaps there is some small sediment impeding the
carb or the float is stuck or similar problem. �Does it seem starved or
rich for fuel-related symptoms?

What shape is the plug? �What about the plug wire; is it in good
condition or could it be cracked from age?

Oh, so many choices... �

--

try removing spark plug, insert some gasoline, reinstall plug and try
to start.

if it runs for a short time its no doubt a clogged carb or fuel line
issue.
this might get it running fine, the engines vacuum may clear the carb
problem

On Apr 30, 9:19*am, Jules Richardson
wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules

If you are getting gas, spark and compression, the thing should run.
The things I would look at first is if it is getting enough gas and
spark. You could try dumping a little gas in the carb and cranking it
over to see if it will start or at least try to start. If it runs at
least a little bit, then take a closer look at the gas delivery
system.

If it doesn't start or at least try to fire up, take out the plug and
see if it is soaking wet. If it is real wet with gas, dry it out and
try again. If it doesn't fire at all, then take a closer look at the
ignition system. You may be getting spark but not enough to fire the
gas.

Also, if you are long overdue to replace this thing and don't get much
satisfaction out of getting an old machine to run and can afford a new
one. Go for it.

David

Jules Richardson wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules


When I was a kid, I discovered that a lawnmower engine would run
on Liquid Wrench. Of course there are carb cleaners that a motor
will run on while cleaning things. I've had luck with spray cleaners
that have the extension tube using it to blow open the tiny ports in
the carb.

TDD

Jeff The Drunk wrote:
On Fri, 30 Apr 2010 09:30:21 -0500, The Daring Dufas wrote:

Jules Richardson wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn
tractor running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for
the cold season, and the grass has got to that point where it needs the
first cut of the year (as soon as this wet spell ends sometime next
week, anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and
is getting gas to the cylinder. I pulled the head and checked the bore
and valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment
is with the needle valve 1-1/2 turns out and idle valve at 1 turn out
(as per manual for "this'll at least allow it to run so you can adjust
the carb"), where it'll *almost* run - it'll fire and turn fast enough
to disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull
the engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after
I've checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules


When I was a kid, I discovered that a lawnmower engine would run on
Liquid Wrench. Of course there are carb cleaners that a motor will run
on while cleaning things. I've had luck with spray cleaners that have
the extension tube using it to blow open the tiny ports in the carb.


When I was a young lad I found out a horizontal shaft Kohler engine would
run on propane from the unlit nozzle of a propane torch held in the
carb venturi. Also found out the motor could easily over-rev and bust the
connecting rod if you fed it too much propane.

Someone comes to me for a job and tells me they have a lot of
experience. I ask them: "How much equipment have you burned up?"
If they answer none, I tell them: "You obviously have no experience,
I need someone who has already burned up thousands of dollars in
equipment because I can't afford it. A learning experience can be
very expensive."

TDD

On Fri, 30 Apr 2010 08:42:40 -0500, dpb wrote:
Does it have a fuel filter? What position is the choke plate in; is it
functioning correctly?

Yes and yes - good flow through the filter, and choke plate closes
correctly.

How did it run last year? You say it's old, is the carb body worn badly
at the throttle plate shaft holes so the air mixture is fouled up
badly--that's a typical failure mechanism with age.

Very much so. I was always surprised it ran at all :-) It always was a
bit picky about starting - I got the knack of tickling the throttle just-
so. The carb is certainly worn, particularly around those shaft holes for
the throttle plate, so I'm under no illusion that it's not the best of
carbs :-) I'm just not sure what's changed since it was run last, though
- whatever carb faults it had shouldn't have grown worse by just sitting
there.

As another posted, perhaps there is some small sediment impeding the
carb or the float is stuck or similar problem. Does it seem starved or
rich for fuel-related symptoms?

It always ran rich (and there was quite a lot of fouling within the head
when I pulled it).

What shape is the plug? What about the plug wire; is it in good
condition or could it be cracked from age?

No *visible* cracks, tip is in good condition (and I checked the gap). If
I pull the plug and ground it, then turn the engine over, it's giving a
healthy-looking spark, although I suppose there's the possibility that
what looks good isn't good enough.

Oh, so many choices...

Yep! It's the figuring out what's changed while it's just sat there which
is probably key, I suppose.

cheers

Jules

On Fri, 30 Apr 2010 07:19:09 -0700, hibb wrote:
If you are getting gas, spark and compression, the thing should run. The
things I would look at first is if it is getting enough gas and spark.
You could try dumping a little gas in the carb and cranking it over to
see if it will start or at least try to start. If it runs at least a
little bit, then take a closer look at the gas delivery system.

If it doesn't start or at least try to fire up, take out the plug and
see if it is soaking wet. If it is real wet with gas, dry it out and try
again. If it doesn't fire at all, then take a closer look at the
ignition system. You may be getting spark but not enough to fire the
gas.

Yeah, I think that's where I'm at - visually, it appears to be doing all
the things it needs to be doing, but there must be something (e.g.
igntion or fuel delivery) that it's not doing well enough - unless some
major drama has occurred in the valve or ignition timing (yuck!).

Also, if you are long overdue to replace this thing and don't get much
satisfaction out of getting an old machine to run and can afford a new
one. Go for it.

Oh, I love getting old stuff going again :-) Problem with this mower is
that it's on extended loan, rather than mine, so I get reluctant to pour
money into spares (and there's a big list of stuff on it that's pretty
much worn out and can't be "fixed" other than by replacing parts).

If it belonged to me I'd strip it all down and fix everything (I could
spend a couple of hundred on parts, I bet, but that's still cheaper than
a new one) and doubtless give it a fresh coat of paint too ;-) But as
it'll probably go back to its owner one day, maybe it's just time to
invest in a replacement.

cheers

Jules

On Fri, 30 Apr 2010 09:32:50 -0400, salty wrote:
If it ran when you parked it for the winter, and it doesn't run now,
then it is almost a 100% certainty that your carb is not as clean as you
think. It needs to be disassembled, soaked in proper carb cleaner, and
all the passages blown clear with compressed air.

Hmm, I'll revisit that. I can pull it and strip it down in less than 5
minutes these days :-) Don't think I have any carb cleaner, although I do
have some brake parts cleaner - maybe that's asking for trouble, though!
(I'm not sure how similar it is)

Then start over with a dry, clean, gas tank and lines. Fill with gas
that you bought within the past month.

Yeah, the gas lines/filter are another possibility I suppose - as I said,
it seems to get good flow from the tank, but I've heard of rubber hoses
essentially delaminating and collapsing internally when they age. As a
test I suppose I can ensure a clean tank and try without a filter (I
think I have some spare new hose somewhere of the right size)

cheers

Jules

On Apr 30, 8:19*am, Jules Richardson
wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules

It runs just not under load right, ive had several 4 motors like that
and it was electrical. One a bad wire, two the ignition module, one
the coil. A motors spark at idle needs not be strong to run, but to
ignite alot of gas for load it needs to be strong. That doesnt rule
out low compression or a carburator-fuel issue but since it runs it
could be electrical. Is the spark small and weak and maybe red in
color, but ive had small blue sparks not enought to go past idle.
Sears sells a 4$ induction tester you just touch the wire while its
running, if the spark is what dies as you load it you should be able
to see it, and squirting gas in the carb with throttle open should
help rule out or confirm a fuel issue. Why did you pull the head?

Jules Richardson wrote:
....

... Don't think I have any carb cleaner, although I do
have some brake parts cleaner - maybe that's asking for trouble, though!
(I'm not sure how similar it is)

Close enough; anything highly solvent that evaporates cleanly will do...

Then start over with a dry, clean, gas tank and lines. Fill with gas
that you bought within the past month.

Yeah, the gas lines/filter are another possibility I suppose - as I said,
it seems to get good flow from the tank, but I've heard of rubber hoses
essentially delaminating and collapsing internally when they age. As a
test I suppose I can ensure a clean tank and try without a filter (I
think I have some spare new hose somewhere of the right size)
....

These small engines if the hose flows it's not the problem. If there is
a filter (many don't, that is a possibility--the w/o it test is easy to
eliminate the possibility of course).

--

On Apr 30, 1:09*pm, Jules Richardson
wrote:
On Fri, 30 Apr 2010 07:19:09 -0700, hibb wrote:
If you are getting gas, spark and compression, the thing should run. The
things I would look at first is if it is getting enough gas and spark.
You could try dumping a little gas in the carb and cranking it over to
see if it will start or at least try to start. If it runs at least a
little bit, then take a closer look at the gas delivery system.

If it doesn't start or at least try to fire up, take out the plug and
see if it is soaking wet. If it is real wet with gas, dry it out and try
again. If it doesn't fire at all, then take a closer look at the
ignition system. You may be getting spark but not enough to fire the
gas.

Yeah, I think that's where I'm at - visually, it appears to be doing all
the things it needs to be doing, but there must be something (e.g.
igntion or fuel delivery) that it's not doing well enough - unless some
major drama has occurred in the valve or ignition timing (yuck!).

Also, if you are long overdue to replace this thing and don't get much
satisfaction out of getting an old machine to run and can afford a new
one. Go for it.

Oh, I love getting old stuff going again :-) Problem with this mower is
that it's on extended loan, rather than mine, so I get reluctant to pour
money into spares (and there's a big list of stuff on it that's pretty
much worn out and can't be "fixed" other than by replacing parts).

If it belonged to me I'd strip it all down and fix everything (I could
spend a couple of hundred on parts, I bet, but that's still cheaper than
a new one) and doubtless give it a fresh coat of paint too ;-) But as
it'll probably go back to its owner one day, maybe it's just time to
invest in a replacement.

cheers

Jules

Yeah, I've got an old Alis Chalmers Rotary Tiller that I am debating
on whether to fix or not. I had not used it in a couple of decades and
my nephew took it a few years ago to try to get it going. When I got
it back, it is missing the gas tank and air cleaner and I am thinking
I just might as well replace the carburetor. I checked on line and the
gas tank is about $70, the air cleaner is about $35 and the carb would
be around $130.

That's about a third of the cost of a new one but If I get this thing
going and take better care of it and use it more, I bet it would last
me for as long as I am able to use it.

David

Jules Richardson wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn
tractor running before I throw in the towel and go buy a
(long-overdue) replacement tomorrow. It's refused to start after
being set aside for the cold season, and the grass has got to that
point where it needs the first cut of the year (as soon as this wet
spell ends sometime next week, anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil.
Fuel line's clear, carb is free of debris. It's got compression,
spark, and is getting gas to the cylinder. I pulled the head and
checked the bore and valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment
is with the needle valve 1-1/2 turns out and idle valve at 1 turn out
(as per manual for "this'll at least allow it to run so you can
adjust the carb"), where it'll *almost* run - it'll fire and turn
fast enough to disengage the starter pinion, then immediately die on
me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull
the engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after
I've checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

Buy a NEW spark plug before you do anything else.

Jon

"Jules Richardson" wrote in message
...

[snip]

Is there a fuel shut-off solenoid inside the carb?

It sounds like you are getting fuel to the carb, just not through the carb.

Sticky float plunger, clogged passages, or partially functioning fuel solenoid
are the usual culprits.

B&S engines have fixed timing.

A partially shorn shaft key might goof up the timing a bit, but the engine
should still run if it fires at all. It's an all or nothing kind of thing.

Concentrate on the carb.

On Fri, 30 Apr 2010 11:06:16 -0700, "Jon Danniken"
wrote:

Buy a NEW spark plug before you do anything else.

Also check the gap before install. Those plugs gapped at the factory
are not always accurate... Get the correct heat range for the plug as
they are not all the same

OP - loosen the gas cap a turn or two. If the cap vent is clogged the
tank will create a vacuum, affecting fuel flow. Clean vent with a
paper clip.

You have plenty of oil in the engine, right. If the motor has a low
oil kill switch that would shut the down engine.

On Fri, 30 Apr 2010 15:22:03 -0500, The Black Knight wrote:

"Jules Richardson" wrote in message
...

[snip]

Is there a fuel shut-off solenoid inside the carb?

No... I'm not sure who made the carb, unless B+S rolled their own. It's a
pretty simple beast really.

It sounds like you are getting fuel to the carb, just not through the
carb.

Well, *something* is getting through because I can pull the carb off and
it's wet on the 'engine side' of the carb body. I wonder that's actually
a sign of the problem, though, and it's just not atomizing the fuel
properly and is getting neat gas pouring into the cylinder rather than a
nice mist (the presence of just enough vapor might explain the way it
tries to cough into life once sometimes, then promptly dies).

OTOH, maybe I'm clutching at straws ;-)

Oh, other possible symptom: the carb's getting a *lot* of gas; it drips
quite a lot from the intake side if I have the air filter assembly off
(the bolt that holds the filter on runs right through the carb body on
the intake). It's possible it's always been like that, and that's normal
behavior, but it surprised me there'd be that much gas "upstream" of the
choke plate.

Sticky float plunger

Possible, I suppose. I checked that the float isn't holed, and the
metering needle there looks good and seems to seat well (the carb sits
slightly lower than the tank, so if there were a float problem I think
I'd get gas pouring out everywhere even with the mower just sitting).

clogged passages

I can't completely rule that out, as there are a couple of passages I
can't really get to (access sealed at the factory), although I can blow
through them, so I know they're not completely blocked.

A partially shorn shaft key might goof up the timing a bit, but the
engine should still run if it fires at all. It's an all or nothing kind
of thing.

I might try to pull the flywheel (which times the ignition) just to check
that - it'd be a heck of a coinicidence if it just happened right at shut-
down last season, but stranger things have happened :-) I've certainly
had keys shear on smaller engines before.

Concentrate on the carb.

Yeah, I just pulled it again and double-checked what I could. I ended up
dumping a little neat brake cleaner into the inlet "upstream" of the
float and throttle, and the engine actually turned about four revs under
its own power before dying (it'd only do about 1 or 2 revs by itself on
gas). I can't decide if that's indicative of anything meaningful or
not :-)

cheers

Jules

On Fri, 30 Apr 2010 10:27:53 -0700, ransley wrote:
It runs just not under load right, ive had several 4 motors like that
and it was electrical.

No, not running at all. I've had it run maybe a couple of revs under its
own power a few times, then it dies on me (it doesn't seem consistent
though - if it fires like that, I can leave the throttle in exactly the
same spot and come back to it a few minutes later, and it won't fire at
all)

Why did you pull the head?

Just to take a look at the valve seats & cylinder bore - only takes a
couple of minutes, and I wanted to make sure the valves looked like they
were seating properly and the bore wasn't trashed for whatever reason.
All appeared OK, though.

cheers

Jules

On Fri, 30 Apr 2010 21:26:48 +0000 (UTC), Jules Richardson
wrote:


A partially shorn shaft key might goof up the timing a bit, but the
engine should still run if it fires at all. It's an all or nothing kind
of thing.

I might try to pull the flywheel (which times the ignition) just to check
that - it'd be a heck of a coinicidence if it just happened right at shut-
down last season, but stranger things have happened :-) I've certainly
had keys shear on smaller engines befor

If you do pull the flywheel, shine the magnets (two) with some emory
cloth. Clean any contacts and shine them.

I've seen surface rust (humid areas) on the flywheel magnets - enough
to diminish the good clean firing of the ignition.

Jeff The Drunk wrote:
On Fri, 30 Apr 2010 11:08:17 -0500, The Daring Dufas wrote:

Jeff The Drunk wrote:
On Fri, 30 Apr 2010 09:30:21 -0500, The Daring Dufas wrote:

Jules Richardson wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn
tractor running before I throw in the towel and go buy a
(long-overdue) replacement tomorrow. It's refused to start after
being set aside for the cold season, and the grass has got to that
point where it needs the first cut of the year (as soon as this wet
spell ends sometime next week, anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil.
Fuel line's clear, carb is free of debris. It's got compression,
spark, and is getting gas to the cylinder. I pulled the head and
checked the bore and valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment
is with the needle valve 1-1/2 turns out and idle valve at 1 turn out
(as per manual for "this'll at least allow it to run so you can
adjust the carb"), where it'll *almost* run - it'll fire and turn
fast enough to disengage the starter pinion, then immediately die on
me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull
the engine and take the bottom cover off to take a look (and check
the governor mechanism*), but it's something of a last resort job
after I've checked everything else.

* I don't think it's that, as I've tried manually holding the
throttle wide open at the carb, overriding what the governor might be
trying to do, and it doesn't help.

cheers

Jules


When I was a kid, I discovered that a lawnmower engine would run on
Liquid Wrench. Of course there are carb cleaners that a motor will run
on while cleaning things. I've had luck with spray cleaners that have
the extension tube using it to blow open the tiny ports in the carb.


When I was a young lad I found out a horizontal shaft Kohler engine
would run on propane from the unlit nozzle of a propane torch held in
the carb venturi. Also found out the motor could easily over-rev and
bust the connecting rod if you fed it too much propane.
Someone comes to me for a job and tells me they have a lot of
experience. I ask them: "How much equipment have you burned up?" If they
answer none, I tell them: "You obviously have no experience, I need
someone who has already burned up thousands of dollars in equipment
because I can't afford it. A learning experience can be very expensive."

TDD

A lot of my experience comes from ****ing **** up beyond what was the
original problem then having to repair both my ****up and the original
****up. You learn quick when it starts cutting into the profits or
downright cost you money out of pocket.

Just repaired a Tecumseh 4 stroke motor the other day. Would want to
start when pulled but sputtered then died. Turned out to be a clogged jet
intake in the carb bowl. It is the bolt that holds the bowl on, hollow
with a screen at the bottom. Also took a .012 guitar string and ran it
through the power and idle jets while I had the carb apart.

I use my welding torch tip cleaner set. Even if you don't own a
gas welding rig, you should have one of those handy cleaner sets.
They're inexpensive and are very useful for a surprising number
of tasks.

http://ecx.images-amazon.com/images/...uL._SS400_.jpg

TDD

Jules Richardson wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules


Something I've noticed on engines like yours is the need for valve
clearance adjustment after the engine has rub for a number of years.
I've worked on a lot of standby generators and the overhead valve
engines are easy to adjust the valves on. The valve in head engines
such as the one I believe you have is a different story. I had one
that would only run if I preheated it with a propane torch which
caused the metal to expand enough to let the valves seal. Here is
a video that explains a lot about dong a valve job on a L head
engine.

http://www.youtube.com/watch?v=2yr5a69TxNI

TDD

Now, that sounds like the voice of experience. I knew a kid
one time who ran an ungoverned lawn mower to get to town and
back. A couple times, until it over revved, and broke.

We recently had a thread about getting home on paint
thinner, when the gas tank was near empty. I've heard gas
engines run well on a spray of WD-40.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Jeff The Drunk" wrote in message
news On Fri, 30 Apr 2010 09:30:21 -0500, The Daring Dufas wrote:

When I was a kid, I discovered that a lawnmower engine
would run on
Liquid Wrench. Of course there are carb cleaners that a
motor will run
on while cleaning things. I've had luck with spray
cleaners that have
the extension tube using it to blow open the tiny ports in
the carb.


When I was a young lad I found out a horizontal shaft Kohler
engine would
run on propane from the unlit nozzle of a propane torch held
in the
carb venturi. Also found out the motor could easily over-rev
and bust the
connecting rod if you fed it too much propane.

Yes, better to kill a few things before they hire on with
you.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"The Daring Dufas" wrote
in message ...


When I was a young lad I found out a horizontal shaft
Kohler engine would
run on propane from the unlit nozzle of a propane torch
held in the
carb venturi. Also found out the motor could easily
over-rev and bust the
connecting rod if you fed it too much propane.

Someone comes to me for a job and tells me they have a lot
of
experience. I ask them: "How much equipment have you burned
up?"
If they answer none, I tell them: "You obviously have no
experience,
I need someone who has already burned up thousands of
dollars in
equipment because I can't afford it. A learning experience
can be
very expensive."

TDD

We could call your equipment Oreos -- double stuffed?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Jeff The Drunk"
wrote in message news

Someone comes to me for a job and tells me they have a lot
of
experience. I ask them: "How much equipment have you
burned up?" If they
answer none, I tell them: "You obviously have no
experience, I need
someone who has already burned up thousands of dollars in
equipment
because I can't afford it. A learning experience can be
very expensive."

TDD

A lot of my experience comes from ****ing **** up beyond
what was the
original problem then having to repair both my ****up and
the original
****up. You learn quick when it starts cutting into the
profits or
downright cost you money out of pocket.

Just repaired a Tecumseh 4 stroke motor the other day. Would
want to
start when pulled but sputtered then died. Turned out to be
a clogged jet
intake in the carb bowl. It is the bolt that holds the bowl
on, hollow
with a screen at the bottom. Also took a .012 guitar string
and ran it
through the power and idle jets while I had the carb apart.

Easy off oven cleaner is excellent for cleaning carbs.
Strips off gum and varnish. Rinse well, and dry before
reassembling. Best carb cleaner I've ever used.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Jules Richardson" wrote
in message ...


Hmm, I'll revisit that. I can pull it and strip it down in
less than 5
minutes these days :-) Don't think I have any carb cleaner,
although I do
have some brake parts cleaner - maybe that's asking for
trouble, though!
(I'm not sure how similar it is)

Champion had a run of bad CJ-8 for a few years. That's a
brand I avoid.

During start, the throttle is wide open, and the choke
closed.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Jon Danniken" wrote
in message ...

* I don't think it's that, as I've tried manually holding
the throttle
wide open at the carb, overriding what the governor might
be trying to
do, and it doesn't help.

Buy a NEW spark plug before you do anything else.

Jon

The mowers I've serviced. if the valve clearance is too low,
the mower runs 15 minutes, fades out, and died. Restarts
after it's cold. I learned that in a small engine repair
course. One guy a couple streets over was going nuts on a
mower repair, and turned out valve clearance was the
problem.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"The Daring Dufas" wrote
in message ...


Something I've noticed on engines like yours is the need for
valve
clearance adjustment after the engine has rub for a number
of years.
I've worked on a lot of standby generators and the overhead
valve
engines are easy to adjust the valves on. The valve in head
engines
such as the one I believe you have is a different story. I
had one
that would only run if I preheated it with a propane torch
which
caused the metal to expand enough to let the valves seal.
Here is
a video that explains a lot about dong a valve job on a L
head
engine.

http://www.youtube.com/watch?v=2yr5a69TxNI

TDD

On Apr 30, 4:38*pm, Jules Richardson
wrote:
On Fri, 30 Apr 2010 10:27:53 -0700, ransley wrote:
It runs just not under load right, ive had several 4 motors like that
and it was electrical.

No, not running at all. I've had it run maybe a couple of revs under its
own power a few times, then it dies on me (it doesn't seem consistent
though - if it fires like that, I can leave the throttle in exactly the
same spot and come back to it a few minutes later, and it won't fire at
all)

Why did you pull the head?

Just to take a look at the valve seats & cylinder bore - only takes a
couple of minutes, and I wanted to make sure the valves looked like they
were seating properly and the bore wasn't trashed for whatever reason.
All appeared OK, though.

cheers

Jules

If compression is to low it wont start easily or at all, you need a
15$ tester to find out the real pressure. Leaking fuel to me means
flooding, is plug wet after you try.

On Fri, 30 Apr 2010 22:09:53 -0400, "Stormin Mormon"
wrote:

Now, that sounds like the voice of experience. I knew a kid
one time who ran an ungoverned lawn mower to get to town and
back. A couple times, until it over revved, and broke.

We recently had a thread about getting home on paint
thinner, when the gas tank was near empty. I've heard gas
engines run well on a spray of WD-40.
Because the propellant is basically Propane - which gets the kerosene
lit. Bulg WD40 won't light worth crap.

On Fri, 30 Apr 2010 22:13:24 -0400, "Stormin Mormon"
wrote:

Easy off oven cleaner is excellent for cleaning carbs.
Strips off gum and varnish. Rinse well, and dry before
reassembling. Best carb cleaner I've ever used.
Just don't forget to rinse promptly. - and thoroughly. On a zinc
carb it's not as bad as on aluminum.

Didn't know that about the propellant. I've never tried bulg
WD40.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


wrote in message
...
On Fri, 30 Apr 2010 22:09:53 -0400, "Stormin Mormon"


Because the propellant is basically Propane - which gets
the kerosene
lit. Bulg WD40 won't light worth crap.

Yes, promptly is good. Within seconds of spraying the oven
cleaner. metals damage due to the strong alkalai, is a very
real possibility.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


wrote in message
...
On Fri, 30 Apr 2010 22:13:24 -0400, "Stormin Mormon"
wrote:

Easy off oven cleaner is excellent for cleaning carbs.
Strips off gum and varnish. Rinse well, and dry before
reassembling. Best carb cleaner I've ever used.

Just don't forget to rinse promptly. - and thoroughly. On
a zinc
carb it's not as bad as on aluminum.

On Fri, 30 Apr 2010 21:06:01 -0400, clare wrote:
Check your local lawn mower "bone yard" for a carb that hasn't got
the bushings all worn out of it and start over with it.

Yes - watch this space... I brought home an almost-identical mower
yesterday, except that it's got the 7-speed transmission and an 11HP B+S
engine (rather than my 5-speed / 10HP). I think the carb's identical
though - I suspect most of the engine is, and it's just a different bore/
stroke.

Actually, the 'new' mower's possibly a better long-term candidate than
the current one. For 15 years of standing out in the open it's pretty
solid. Front axle and tires are shot, and there's something up with the
deck, but those would swap over easily enough.

I think I'll use engine parts from it to get my current one going (I can
last about one more week before mowing), but after that screw around with
it some and see if I can get it up and running.

cheers

Jules

On Fri, 30 Apr 2010 22:14:44 -0400, Stormin Mormon wrote:

Champion had a run of bad CJ-8 for a few years. That's a brand I avoid.

During start, the throttle is wide open, and the choke closed.

Yep - I was just ruling out a governor problem by manually holding the
throttle (just in case the governor was screwed and trying to throttle
things way back before the engine had chance to cough into life)

On Fri, 30 Apr 2010 13:19:10 +0000, Jules Richardson wrote:
The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and
is getting gas to the cylinder. I pulled the head and checked the bore
and valve seats, and no obvious problems there.

I'm wondering about the compression, now. Can low compression result in
an engine that won't even start/run under no load?

It's got some compression for sure (nice healthy hiss from the crankcase
breather on the down-stroke if I turn by hand), but I tore into the 11HP
engine from the donor mower I picked up at the weekend, and that engine's
piston fits *far* more snugly in the bore than on the 10HP. It slides
well (so no apparent issue with ears of it sitting there unusued), but
fits better with no detectable side-to-side movement if I try wobbling
it, unlike the 10HP.

(Although if it is a compression issue, I still don't get why it was
running last season and magically broke over the winter...)

Oh, I cleaned up the carb on the 11HP and tried it on the 10HP. It will
fire consistantly for maybe 4-5revs, then die, so not really any better
than the 10HP's own carb was. No different swapping the plug, either.
Magneto is unfortunately trashed on the 11HP, so I can't try swapping
that.

cheers

Jules

Jules Richardson wrote:
....

I'm wondering about the compression, now. Can low compression result in
an engine that won't even start/run under no load?

Certainly, but it has to be pretty doggone low to not run at all...

It's got some compression for sure (nice healthy hiss from the crankcase
breather on the down-stroke if I turn by hand), ...

If you can use a thumb in the spark plug hole and keep it from blowing
by, it's a good chance it is that bad...

--

On Apr 30, 9:19�am, Jules Richardson
wrote:
(does this count as "home", or is there a better place for it?)

I think today's the last chance for getting our elderly MTD lawn tractor
running before I throw in the towel and go buy a (long-overdue)
replacement tomorrow. It's refused to start after being set aside for the
cold season, and the grass has got to that point where it needs the first
cut of the year (as soon as this wet spell ends sometime next week,
anyway)

The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and is
getting gas to the cylinder. I pulled the head and checked the bore and
valve seats, and no obvious problems there.

I've got the service manual, and the best it's managing at the moment is
with the needle valve 1-1/2 turns out and idle valve at 1 turn out (as
per manual for "this'll at least allow it to run so you can adjust the
carb"), where it'll *almost* run - it'll fire and turn fast enough to
disengage the starter pinion, then immediately die on me.

Any ideas what else to look at? I wondered about timing, but it seems
unlikely that's out unless the cam gear jumped a tooth. I could pull the
engine and take the bottom cover off to take a look (and check the
governor mechanism*), but it's something of a last resort job after I've
checked everything else.

* I don't think it's that, as I've tried manually holding the throttle
wide open at the carb, overriding what the governor might be trying to
do, and it doesn't help.

cheers

Jules

First.......put in a new plug. Just because it fires, doesn't mean the
plug is good. I have seen engines run (poorly) with a bad plug.

You say it has compression, but does it have enough. Just because the
valve seats look good, doesn't mean the are closing all the way. Check
the gap, should be approx. .04

Hank

On Wed, 5 May 2010 17:53:42 +0000 (UTC), Jules Richardson
wrote:

(Although if it is a compression issue, I still don't get why it was
running last season and magically broke over the winter...)

One of the piston rings froze up?

On May 5, 12:53*pm, Jules Richardson
wrote:
On Fri, 30 Apr 2010 13:19:10 +0000, Jules Richardson wrote:
The engine's a 10HP B+S with electric start. Fresh gas, fresh oil. Fuel
line's clear, carb is free of debris. It's got compression, spark, and
is getting gas to the cylinder. I pulled the head and checked the bore
and valve seats, and no obvious problems there.

I'm wondering about the compression, now. Can low compression result in
an engine that won't even start/run under no load?

It's got some compression for sure (nice healthy hiss from the crankcase
breather on the down-stroke if I turn by hand), but I tore into the 11HP
engine from the donor mower I picked up at the weekend, and that engine's
piston fits *far* more snugly in the bore than on the 10HP. It slides
well (so no apparent issue with ears of it sitting there unusued), but
fits better with no detectable side-to-side movement if I try wobbling
it, unlike the 10HP.

(Although if it is a compression issue, I still don't get why it was
running last season and magically broke over the winter...)

Oh, I cleaned up the carb on the 11HP and tried it on the 10HP. It will
fire consistantly for maybe 4-5revs, then die, so not really any better
than the 10HP's own carb was. No different swapping the plug, either.
Magneto is unfortunately trashed on the 11HP, so I can't try swapping
that.

cheers

Jules

A compression gauge is cheap, maybe 15$ and will tell you all you need
to know before wasting any time on a junker. I cant give accurate
numbers but I will guess and say 130 is new, 110 its at half life and
near 80-85 its not going to want to do anything. Try misting in gas
with a hand spray bottle just as it starts.