Engine keeps stalling

[MCNPathfinder]

I have a 22' cabin cruiser with a Chevy 305 in it that's having trouble continuously running. It keeps dying. We had it out on the water for the first time last night. I ran it on muffs in the driveway and didn't seem to have any problems with it. As soon as you apply any sort of throttle to it, it dies. I didn't seem to have this problem on the muffs. If you can get it started at like a 1/4 throttle, it'll let you rev it, but as soon as you go down and then back up it'll bog down and quit.
We ran it without the doghouse on it and if you were able to get it in gear, as soon as you applied more than idling throttle do it, you could hear it start "sucking" in air louder, but it would just bog down and quit. Could it be bad gas? I just don't understand how it could if it was running okay on muffs. I added about 12 gallons of premium to whatever was in there from last season. I would guess 5 or so gallons of premium.
I've never had really any problems with this boat, it's always been really reliable. I kind of forgot the feeling of being that guy who spends his whole trip out fixing the boat rather than enjoying the lake.
Any ideas on where to start?
Thanks!

 

[Watermann]

Re: Engine keeps stalling

Sounds like a fuel delivery problem. The fuel filter plugged or fuel pump could be weak. If it continues, could be the carb needs cleaned out or rebuilt. Good time for a tune up and some fuel system maintenance.

 

[hulakai]

Re: Engine keeps stalling

What kind of fuel filter do you have? A motor doesn't require a lot of fuel to rev without a load on it.....sure sounds like it's starving for gas when it's in the water. How old is it? Has the carb been replaced/rebuilt ever? Did you add fuel stabilizer and run it through a bit before you stored it?

Just some ideas....I'm not pro by any means. I've having problems with my own 5.0L running rough at idle and if I don't keep the idle up a bit, it will stall. Runs fine at speed though. Hoping it's a bad carb gasket or something.

 

[hulakai]

Re: Engine keeps stalling

Good point Watermann.....if it's electric fuel pump you should check the pressure coming out of it... if none of the other things fit. Consider running it from a portable gas tank if you can....that will tell you if it's bad fuel.

 

[MCNPathfinder]

Re: Engine keeps stalling

Thanks for the responses! After some tinkering, we're thinking it's a fuel pump problem. Apparently these engines are known for their fuel pump failures. It's not an electric and it's run off the crankshaft I think? It's bolted to the side of the engine, so I guess I should get out the manual.
Just bouncing some ideas off you guys on why we think we have a fuel pump issue. So to get it started, I generally have to pump the throttle a few times, start it, and then it's ok. It'll idle fine for a few minutes then stall. If I apply any sort of throttle it hesitates and dies. I'm thinking the fuel pump is supplying just enough to keep it running, but not enough to keep it running for a long period of time, so it stalls. Then when it's requiring more gas, the fuel pump just can't keep up.
The only reason we think the carb is probably ok, is because it idles really smoothly (it's a beautiful sound, it really really is ;-) ... )
So I think my next step is to try a new fuel pump. I replaced the fuel filter last year with a Quicksilver filter as recommended by the marina. As far as new fuel pumps go, is this something I can just get from Napa or some auto parts store or does it need to be marine rated for fire purposes and what not?
Thanks again for the help guys!

 

[Watermann]

Re: Engine keeps stalling

The fuel pump should be an easy replacement, they use a rod that runs on the camshaft to actuate the lever on the pump. 2 fuel lines and 2 bolts to remove is all there is to it. Yeah NAPA will have a new pump, no fire rating that I know of on a fuel pump unless they leak...

 

[MCNPathfinder]

Re: Engine keeps stalling

The fuel pump should be an easy replacement, they use a rod that runs on the camshaft to actuate the lever on the pump. 2 fuel lines and 2 bolts to remove is all there is to it. Yeah NAPA will have a new pump, no fire rating that I know of on a fuel pump unless they leak...

Freaking sweet! I hope that fixes it. My family will be extremely happy if we can get out this weekend. Thanks for the advice and help!