Engine Starts and runs strong for 10 min., then stalls and shuts off!

[horacito]

What a great forum! I have searched for an answer to my question on the forum, but am still unsure how to proceed. A couple of months ago my engine developed a problem where it would shut down after 30 or so minutes of use but would restart immediately. This problem became progressively worse and eventually would shut down every few minutes, but always restarting. Well I think that all this repeated starting eventually burned out the starter which I recently replaced. The engine would now start, run for about ten minutes and then shut off. After this it would not start again. it definately sounded starved for fuel so I checked the fuel lines and replaced the Racor filter last weekend. Same story, engine will start and run strong for about 10 minutes, then shut off and not restart. I have called several mechanics who are willing to come out but none of them specialize in atomic 4's and being a teacher I am low on funds. I would really like to learn how to take care and troubleshoot of my own engine so any suggestions would be appreciated.

[Don Moyer]

The surest way to determine if your shutdowns are fuel or ignition related is to run the small checklist the next time the engine shuts down and will not start.

The other two attachments should get you started troubleshooting once you determine which system is at fault. If you determine that fuel is causing the shutdowns, you might also check for a blockage in the fuel tank vent line. Blocked vent lines will frequently cause a shutdown after about 40 minutes of operation.

Don

[horacito]

I thought it was fixed

Don and friends,

I had a mechanic come out and troubleshoot the engine. After a few tests he determined it was the fuel pump. He had the part available for $210...Yikes! Good thing I knew how to find the part at Moyer Marine for $97 and he was ok with me supplying my own part. I ordered on Thursday of last week and had the part in hand Monday afternoon. After recieving the part I started poking around my Catalina 27 and discovered perfect access to the fuel pump and carb. I saw the electric fuel pump and realized how easy it would be to change, not really having to much experience with engines I was hesitant at first but I dived in and proceeded to change it. After swapping it out my old A4 started right up. She purred and ran strong for 30 min at all rpm levels. After 30 min I shut the engine off and then turned it back on. It started right back up w/o the choke and ran strong again.
I left my boat feeling like a million bucks and so happy I saved the $$$. With spring break coming up next week all i could think about was "getting out there" again. Well, i go out there today to give the ol girl a bath and I thought let me start the engine just to hear it purr again.....Well it started ok and then sputured out. I tried to start it again ran for one second then went out. Then nothing. Tried and tried, it never turned over again. I am so frustrated!! It ran so well yesterday, but today it's like i never replaced the pump. I was very careful to install the pump exactly the way it was before. The only thing I noticed is that I do not have a fuel filter between the pump and carb as pictured in some of the engines I have seen on the sight, although I believe this has nothing to do with the problem. Any help would be appreciated before I have to call the mechanic back....

[Don Moyer]

Horacito,

I should have mentioned that your inline fuse may have blown between the positive terminal of the coil and the oil safety switch.

Don

[Don Moyer]

Congratulations on a good job changing your pump!

I'm attaching a couple tech notes in case you didn't see them before to help you identify where your problem might be in the fuel supply system.

Don

[horacito]

Thanks!

Don, Thanks for all your help...My engine is up and running and sounds great. Your last suggestion to me ws to install a priming bulb between the gas tank and racor filter. This $12 fix helped my engine start right up and hasn't shut down even once since the install. This success has given me the confidence to fix my own engine, and tackle more complex issues.....I see a carb rebuild in my future. Thanks again, and for anybody who doesn't have a priming bulb installed I would highly recommend it!

[alberg]

Prime bulb

Wow!!

I am some what surprised that anyone would use a flexable rubber device in a gas line. According to coast guard and ABYC you cannot use a glass or plastic inline filter with gas because it might fracture letting gas out. It seems to me that a rubber bulb would be more likely leak.

john
Alberg

[tenders]

Glass and plastic are very brittle and are prone to fail totally when confronted with events that regularly occur on boats -- things flying around. Rubber, not so much. It's a much better material for fuel lines than brass, really, because it doesn't fatigue like brass and can be spliced or replaced cheaply and without special tools or careful measuring. You can also move it around to inspect it.