GM 140 problems

[dtwallace84]

Just put a new exhaust manifold on my GM 140. I put it on the water yesterday and when I get on the throttle at about 1000 RPM it begins to backfire. I can slowly push through this to full throttle at 3500 RPM but it isnt going full speed. It will slowly gain speed at full throttle but still wont get to max speed. I know theres nothing wrong with the gas. If the timing was off a little would this be the problem?

 

[Bondo]

Re: GM 140 problems

I know theres nothing wrong with the gas. If the timing was off a little would this be the problem?

How do you Know it's getting enough Gas,...??...

The Symptoms you describe is Classic Fuel Starvation.........

When was the last time the motor was Tuned Up,..??

What are the Sparkplugs telling you,..??..... ei. What Color are they,..??

 

[DHPMARINE]

Re: GM 140 problems

More info would help.

How did it run before the new manifold,and why was it replaced?

DHP

 

[dtwallace84]

Re: GM 140 problems

there was a crack in the manifold and it was letting water into the cylinders. The plugs look good but they have only been ran on about 30 min and im getting gas into the carb but im not sure if I have the mixture screw in good tune. I took fuel pump apart and changed filter and there was gas in there.

 

[Bondo]

Re: GM 140 problems

When was the last time the motor was Tuned Up,..??

 

[dtwallace84]

Re: GM 140 problems

end of last year

 

[Speedylifsavr]

Re: GM 140 problems

Is it backfiring through intake or exhaust . You mentioned water in motor , how much are we talking? Did it hydrolock? Was motor flushed properly post water intake?