Engine cuts out, restarts ok

[egallion]

My engine starts fine, then abruptly cuts out. When I hit the starter it starts right back up. On a cold start this happens several times before I get stable running, then it will run for 5 minutes or so before cutting out again. This will keep happening as long as i run the motor.
My electric fuel pump will not prime the carb if I have let air into the lines, such as when I replaced the primary fuel filter to try to fix this, thinking I had bad gas or water in it. I use a priming bulb temporarily to remove the air so I get fuel flow. From other posts it appears that this is normal, and I should install a priming bulb. Is it possible that the pump is not supplying enough fuel? Any Ideas on the abrupt cut-out, restart cycle?

[Ando]

Carb?

I hated that when it happened to me. Haunted me actually. Reading the forum, I narrowed it down to the carburetor. What’s the history of your carburetor?

[JOHN COOKSON]

Does closing the choke a bit help? Is the choke fully open and closed when you think it is?

ex TRUE GRIT

Edit: A fuel pressure gauge would be helpful ........

[Al Schober]

For difficulty with cold start, the choke operation is a concern. But 5 minutes of running should be adequate to not need the choke. You've got something else going on. First guess would be the fuel pump.
Second John's recommendation. Install a pressure gauge in the line feeding the carb. Then you'll know if you have a fuel issue.

[JOHN COOKSON]

This is sort of far out but still a possibility. It happened to me twice. The engine would run fine until just about the time I pushed away from the dock. Then it would quit.
The OPSS can fail in all sort of weird manners. Try bypassing the OPSS and see what happens.

ex TRUE GRIT

BTW What is your oil pressure?

[egallion]

I hated that when it happened to me. Haunted me actually. Reading the forum, I narrowed it down to the carburetor. What’s the history of your carburetor?

I rebuilt the carb beginning of last year - big improvement in running, no problems since. This is a new development this year. It does seem somehow to be fuel/carb related

[egallion]

This is sort of far out but still a possibility. It happened to me twice. The engine would run fine until just about the time I pushed away from the dock. Then it would quit.
The OPSS can fail in all sort of weird manners. Try bypassing the OPSS and see what happens.

ex TRUE GRIT

BTW What is your oil pressure?

Not to be a dummy - but what is OPSS?

[egallion]

For difficulty with cold start, the choke operation is a concern. But 5 minutes of running should be adequate to not need the choke. You've got something else going on. First guess would be the fuel pump.
Second John's recommendation. Install a pressure gauge in the line feeding the carb. Then you'll know if you have a fuel issue.

I use the choke only briefly to start, then off. Doesn't seem to matter if I try keeping choke on longer. Engine runs fine without choke on cold start - maybe mixture too rich? Anyway - what sort of fuel pressure should I have? Does the fact that the pump will not purge air from the lines unassisted mean anything?

[Peter]

OPSS - oil pressure safety switch - cuts power to fuel pump if oil pressure gets too low. Good protection for engine and required by USCG

Fuel pressure - pump recommended by Moyer is rated for 2.5-4 psi

A fuel pressure gauge is an excellent diagnostic tool. Make sure you install a metal one - plastic would melt if you had an engine compartment fire and provide fuel to the flames!

Peter

[JOHN COOKSON]

Not to be a dummy - but what is OPSS?

The dumb questions are the ones that are not asked.

If you mouse over underlined acronyms a bubble will appear with the meaning.

The OPSS is a "normal open" switch that closes when the oil pressure rises. A OPSS is safety feature manned by the Coast Guard so the fuel pump will not operate unless the engine is running. The OPSS is usually located a bit below the fuel pump towards the transmission. There will be a wire from it to the fuel pump. On the other OPSS terminal will be a wire bringing electricity to the fuel pump - usually from coil +. Sometimes owners will move the OPSS to a different location for ease of access.

ex TRUE GRIT

[roadnsky]

Do you know what fuel pump you have?
Is it a Facet?

[Tim]

Sounds like you have some debris in the carb bowl that is blocking the main jet. Try taking the carb apart and check for particles/debris in the bowl and make sure the main jet is clear.
If that's not it, you can take the fuel line off the carb try pumping some fuel into a jar to verify the pump is working.