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Not a Car but it is a Chevy 350

I have a '89 Chevy 350 v8 in my boat. It starts fine, but then stalled when decelerating, and would not start. I smelled some gas fumes when trying to start it after it had died. It started up fine the next day without problems. The distributor was just replaced so I know that is good. Not sure if this is related, but occasionally it will diesel a couple cycles when I turn it off.

Could this be the carburetor, or something else?

Thanks.

What’s the fuel tank made of?

While not a boater, I’ve heard frequent horror stories of what ethanol-based fuels will do to fiberglass-based fuel tanks on boats. I’d suspect a clogged fuel filter or carb.

Remove the in-line filter (if installed) and cut open to inspect (not with a cutting wheel, LOL.)

I would suspect that the needle and seat in teh carburetor are leaking, IF it has a carburetor. In 89, it could be a single point fuel injector system, they look like carburetors to the untrained eye. If it is SFI, then you might have a problem with the fuel pressure regulator. But all this is only a guess, a problem like this takes “eyes on”.

I am going to say it sounds like a carb problem, too rich to be exact… Was the timing re-set when they replced the distributor? Was it the whole distributor or just the cap?

Is it carbureted or injected?? By 1989, GM was using TBI, Throttle Body Injection, on their truck engines…But marine conversions might still be using a Quadrajet…

Some details would be nice. Did it do this prior to the distributor swap? Who put in the new distributor? Why was it replaced?

It is a carburetor, Rochester 4MV. It is classified as a quadrajet. I am thinking that may be the problem.

The whole distributor was replaced. I will recheck the timing too.

Thanks for your input.

Pull and check the pick tube in the gas tank. There were some that were a plastic tube press on to the fitting. Mine would suck air at weird times. Always started and ran good till it would suck air. Its a easy fix. I put seal all on it first to make sure that was the problem. I then replaced it with a metal tube. As to the distributor you put in, check the advance. If it sticks it will do this too. But it most times wont restart.

An '89 marine motor would have a carburetor, many use the Holley 4160 4 bbl. It seems you have a Rochester. Sounds like a sticky float. Ethanol gas isn’t good for old marine motors. You might want to start using the new “blue” Stabil which is formulated to deal with ethanol in old marine motors.

I think you need to pull the covers off the floats and see if you have some dirt and debris in the float bowls. Then make sure the floats are free and not sticking. Once cleaned out reinstall the float covers and see how you do. I found I need to replace my inline fuel filter every few seasons. You have one somewhere between the fuel tank and your fuel pump, find it and replace the filter. A good filter should keep junk out of the carburetor.

One a hot day, vapor-lock can be an issue too. Marine engine compartments can get pretty warm…