I have a riding mower with a CV-12 engine. Sometimes it stops as if out
of gas. If I remove the gas cap and wait a moment, a stream of bubbles
from the fuel line will bubble up through the fuel. Then it will start
quickly and run fine.

I don't see what could be getting pumped up with air except the fuel
pump. It's two check valves and a diaphragm operated by a nylon lever.
The outlet check valve is at the top, so I don't understand how the
pump could accumulate air.

Has anyone else run into this problem?

On 05/21/2014 09:45 PM, J Burns wrote:
I have a riding mower with a CV-12 engine. Sometimes it stops as if out of gas. If I remove the gas cap and wait a moment, a stream of bubbles from the fuel line will bubble up through the fuel. Then it will start quickly and run fine.

I don't see what could be getting pumped up with air except the fuel pump. It's two check valves and a diaphragm operated by a nylon lever. The outlet check valve is at the top, so I don't understand how the pump could accumulate air.

Has anyone else run into this problem?

Maybe the vent on your gas cap is plugged?

Maybe the fuel pump is going south?

On Thursday, May 22, 2014 4:41:27 AM UTC-4, Chuck Finley wrote:
On 05/21/2014 09:45 PM, J Burns wrote:

I have a riding mower with a CV-12 engine. Sometimes it stops as if out of gas. If I remove the gas cap and wait a moment, a stream of bubbles from the fuel line will bubble up through the fuel. Then it will start quickly and run fine.



I don't see what could be getting pumped up with air except the fuel pump. It's two check valves and a diaphragm operated by a nylon lever. The outlet check valve is at the top, so I don't understand how the pump could accumulate air.



Has anyone else run into this problem?



Maybe the vent on your gas cap is plugged?



That would be my first suspicion too. He could try
leaving the cap loose for awhile and see what happens.



Maybe the fuel pump is going south?

On 5/22/14, 7:55 AM, trader_4 wrote:
On Thursday, May 22, 2014 4:41:27 AM UTC-4, Chuck Finley wrote:
On 05/21/2014 09:45 PM, J Burns wrote:

I have a riding mower with a CV-12 engine. Sometimes it stops as
if out of gas. If I remove the gas cap and wait a moment, a
stream of bubbles from the fuel line will bubble up through the
fuel. Then it will start quickly and run fine.



I don't see what could be getting pumped up with air except the
fuel pump. It's two check valves and a diaphragm operated by a
nylon lever. The outlet check valve is at the top, so I don't
understand how the pump could accumulate air.



Has anyone else run into this problem?



Maybe the vent on your gas cap is plugged?



That would be my first suspicion too. He could try leaving the cap
loose for awhile and see what happens.



Maybe the fuel pump is going south?

Thanks, Trader and Chuck. I hesitated to remove the pump because it was
grimy outside. WD-40 and degreaser fixed that. I found it clean
inside. The valves work freely and the diaphragm looks fine.

I'll go with the gas cap theory because I have no other ideas. I
haven't figured out why this would cause cause air to accumulate under
pressure in the pump. It must be under pressure if it comes out after I
unscrew the tank cap.

After it has sat a couple of says, it takes a lot of cranking to start,
as if the tank had sucked the pump dry. There's a catch: I turn the
fuel shutoff when I leave it parked.

I squirted some contact cleaner into the vent hole in the cap. I'd love
to take it apart. Maybe I can find instructions online.

On Thu, 22 May 2014 14:16:47 -0400, J Burns
wrote:

Thanks, Trader and Chuck. I hesitated to remove the pump because it was
grimy outside. WD-40 and degreaser fixed that. I found it clean
inside. The valves work freely and the diaphragm looks fine.

I'll go with the gas cap theory because I have no other ideas. I
haven't figured out why this would cause cause air to accumulate under
pressure in the pump. It must be under pressure if it comes out after I
unscrew the tank cap.

If the gas cap vent is clogged, it creates a vacuum in the fuel tank.
Eventually stops the engine.

Loosen the cap first. If it stays running for an extended period, then
it is likely the gas cap. Test that and afterwards you can clean the
vent with a paper clip or buy a new gas cap. IME
--
I like Guns and Titties

On 5/22/14, 2:32 PM, Oren wrote:
On Thu, 22 May 2014 14:16:47 -0400, J Burns
wrote:

Thanks, Trader and Chuck. I hesitated to remove the pump because it was
grimy outside. WD-40 and degreaser fixed that. I found it clean
inside. The valves work freely and the diaphragm looks fine.

I'll go with the gas cap theory because I have no other ideas. I
haven't figured out why this would cause cause air to accumulate under
pressure in the pump. It must be under pressure if it comes out after I
unscrew the tank cap.

If the gas cap vent is clogged, it creates a vacuum in the fuel tank.
Eventually stops the engine.

Loosen the cap first. If it stays running for an extended period, then
it is likely the gas cap. Test that and afterwards you can clean the
vent with a paper clip or buy a new gas cap. IME

I blew into the vent. It's a plain open vent: no valves.

I had a lot of trouble starting and couldn't keep it running. I found
almost no fuel flow. When I suspected the fuel pump last fall, I found
a good flow. This time, when I took the pump off and worked the lever,
I got a good flow. Aha, no pressure! I should have thought of that
last fall.

The spring-actuated valves are like flexible washers. I'll bet they're
supposed to be rigid. Must be the gas! I just can't get good gas these
days. I shop around, but nobody around here sells the $4 stuff anymore,
and they're not willing to special order it for me. What this town needs
is an airport!

The pump is on order. I'll look for some tubing to bypass the pump.
The tank is higher than the carburetor. I guess Kohler included a pump
in case I wanted to mow upside down.

"J Burns" wrote in message
...
The spring-actuated valves are like flexible washers. I'll bet they're
supposed to be rigid. Must be the gas! I just can't get good gas these
days. I shop around, but nobody around here sells the $4 stuff anymore,
and they're not willing to special order it for me. What this town needs
is an airport!


Have you looked at this site to see if anything is near you ?
http://pure-gas.org/

They list many stations that have ethanol free gas.

I switched to the ethanol free gas a couple of years ago for the small
engines and just to be sure I add in some Sta-bil to the gas. Sofar all my
small engines start and run fine. It may be over kill, but it only costs a
few dollars more per year.

On 5/22/14, 6:10 PM, Ralph Mowery wrote:

"J Burns" wrote in message
...
The spring-actuated valves are like flexible washers. I'll bet they're
supposed to be rigid. Must be the gas! I just can't get good gas these
days. I shop around, but nobody around here sells the $4 stuff anymore,
and they're not willing to special order it for me. What this town needs
is an airport!


Have you looked at this site to see if anything is near you ?
http://pure-gas.org/

They list many stations that have ethanol free gas.

I switched to the ethanol free gas a couple of years ago for the small
engines and just to be sure I add in some Sta-bil to the gas. Sofar all my
small engines start and run fine. It may be over kill, but it only costs a
few dollars more per year.

Thanks, I see there's a place 6 miles from me. I wonder how they get
away with it. I thought summer gas was required to have ethanol to
reduce emissions.

Actually, it didn't occur to me that ethanol might have softened my
valves. My remarks about good gas were in fun. Whenever the price of
gas drops, I like to say I'm disappointed that I can't get the good
stuff they used to sell. At one time, when gas was red, I liked to stop
at Amoco stations to get white gas because my motorcycle seemed to run
better. Then I found out that in some parts of the country, Amoco was
red and some other brand was white.

"J Burns" wrote in message
...
Have you looked at this site to see if anything is near you ?
http://pure-gas.org/

They list many stations that have ethanol free gas.


Thanks, I see there's a place 6 miles from me. I wonder how they get away
with it. I thought summer gas was required to have ethanol to reduce
emissions.

Actually, it didn't occur to me that ethanol might have softened my
valves. My remarks about good gas were in fun. Whenever the price of gas
drops, I like to say I'm disappointed that I can't get the good stuff they
used to sell. At one time, when gas was red, I liked to stop at Amoco
stations to get white gas because my motorcycle seemed to run better.
Then I found out that in some parts of the country, Amoco was red and some
other brand was white.


The ethanol gas has been blamed for many engine problems. I have a 5 kw
generator and had to clean out the carborator 2 times before swithcing to
the EFG. Also it runs smoother when unloaded on the EFG. The ethanol also
is bad on some plastic parts, especially the old engines.

I think they have to sell so much ethanol so some stations can get away with
having gas without any in it on one grade of gas.

I remember using the Amco white gas in a car I had with a high performace
engine about 40 some years ago. It was either that or the Sunoco 260.
Everything else sparked knocked.