Chevy 350 stumbling problems

[diablo.243]

I have a 25' Allglass with a new(reman) 350 GM fresh water cooled in it. I just recently purchased the boat and the motor had about 5 hours or so on it when I bought it. After running for 20 minutes or so the motor seems to stumble and have power loss. I have replaced the fuel seporators 3 times, added plenty of water converter to the fuel, took apart the carb and no signs of water, replaced cap and rotor, checked all the plugs, replaced the coil and nothing...... I'm a bit stumped at this point and am looking for advice???? Thanks in advance for any info and help.

 

[hondon]

Re: Chevy 350 stumbling problems

It sounds like with all this water in the fuel activity going on you might be showing signs of water on the spark plugs?If that is so you have not let us know.What is happening to you?Are you launching on a steep ramp ?Did those rebuilders forget the flappers in your exhaust manis?Why are you so worried about water in your fuel?

 

[diablo.243]

Re: Chevy 350 stumbling problems

The reason for concern with water in fuel is that everyone at every marina here said "of it sounds like water in the fuel" when I got the boat it had a small amount of gas in each tank and had sat for at least a year, so water was a legitamate concern. The boat has exhasut flappers, the spark plugs are fine and show perfect burn and wear and the boat is kept at a dock not trailered. With all that out the way I'm looking for the next progression of troubleshooting. Should I be looking at the timing? or if it was timing wouldn't it always run crappy not just after 20 minutes or so? Also I noticed the distrib does not have a vaccum advance, is this normal? and would it be benificial to convet to it????? These are the questions I'm looking for answers for. Thanks

 

[akriverrat]

Re: Chevy 350 stumbling problems

marine distributors do not have vacumn advance as a rule. you don't say what type and make drive you have, what engine you replaced, points and condensor or electronic, or whos marine parts adorn this chevy? too many details are seldom a problem. unless you type like me.

 

[magster65]

Re: Chevy 350 stumbling problems

After 20 minutes of running... <br />If your ignition is happy and your plugs are indeed perfect, check to see your choke is coming off properly. If it is, set your idle mixture and see how that is.