Motor starting then stalls out

[Eriahl92]

So this is my very first post and I’m sorry if I’m not doing his right I’m new to forums. I got ahold of a 1978 sea ray. Has a mercruiser 228 in it. We had a fuel issue with the pump not working properly. It would run long enough until it sucked all the fuel from the water separator then die. We have since then gotten that issue fixed with a new pump and are getting good fuel flow to the carb. But now will only start and run maybe 30 seconds while I pump the throttle. It’s not flooding it will restart and run as many times as you want, but die out quick. Do you think I have an issue in the carb? This boat is a whole restoration. But until I get this motor running great, I’d hate to start on other projects. It’s a 4 barrel quadrajet carb. Any help is needed or if there are threads of this could you point me in he right direction. Got it a few months ago. It was last registered in 09.

 

[Rick Stephens]

I would start with a careful and complete carburetor rebuild. You might also try checking fuel pressure. Most vacuum gauges also are able to be used to check fuel pressure. There are some nice adapters made to plug one into the fuel line where it screws into the carburetor. Is the fuel in the tank clean new and fresh? If not, you should drain clean and refill. A pressure test will tell you if something is plugged up and causing your problem.

 

[Eriahl92]

I’ll start with the carb tonight. I used an electric pump to get all the fuel out of the tank. Pumped out around 25-30 gallon of what smelled and looked like very old gas. It sat for a long time without a cover.

 

[Bondo]

We had a fuel issue with the pump not working properly. It would run long enough until it sucked all the fuel from the water separator then die.
I used an electric pump to get all the fuel out of the tank. Pumped out around 25-30 gallon of what smelled and looked like very old gas. It sat for a long time without a cover.

Ayuh,...... Welcome Aboard,..... This sounds like the earlier problem was up-stream of the fuel pump, more so than the fuel pump itself,.....

I'm guessin' the Entire Fuel System is in need of attention, from the tank to the carb, includin' the tank, 'n carb,......

 

[Eriahl92]

I checked all the fuel lines. Replaced the rubber line with new and made sure the steel lines were clean. There’s no check valve on the tank. For the time being I put an inline primer to make sure I had fuel up line so I was cranking continuously every time. I’m getting great fuel to the carb. But again not sure why it will only run about 30 seconds now why I’m pumping the throttle. Maybe after my initial runs before replacing the pump I threw some junk into the carb. Iv done many rebuilds on my old tractors but never tackled anything like a Rochester. Dropped it off today after work and having someone go through it for me. That way it doesn’t slow me down on anything else. 2 rebuilds currently in process and it’s overwhelming a bit and stressful on the wife haha. Brought the second one home late lastnight. I have a lot of learning ahead of me.