cuts off at wot

[joeneal1986]

i have a 1989 mercruiser with the 4.3 with a 2bbl carb. the boat idles and cranks fine but as soon as u put the hammer down it falls on its face to the point it cuts off. it only does in under a load i have already replaced the power valve, and the fuel filter, and the acc. pump is working fine any ideas

 

[Bt Doctur]

Re: cuts off at wot

Colgged tank vent hose or vent firring or sticking anti-syphon valve

 

[joeneal1986]

Re: cuts off at wot

it just started doing after the carb was rebuilt i also checked the high speed jets if they where clogging and they where

 

[Amy-Lynn]

Re: cuts off at wot

did you find out why it was doing it because i have a similiar problem

 

[ErieRon]

Re: cuts off at wot

it just started doing after the carb was rebuilt i also checked the high speed jets if they where clogging and they where

Most common cause is fuel starvation. As you demand more fuel, more debris is drawn into places it shouldn't be. Sounds like a bad rebuild. It's a tedious process that requires extreme attention to detail. There are no shortcuts. The smallest foreign material in the carb can cause a lot of problems.

So, replace all of your fuel filters (carb, fuel pump & fuel/water separator) and rebuild your carb again, or have it done professionally.

 

[T-Bone Coug]

Re: cuts off at wot

Carb float not allowing the bowl to fill up properly could also cause the problem. Check float level to make sure it is properly adjusted. If it has too much distance between gasket face and float when float is up, then it may not drop far enough to open the valve all the way.

 

[Amy-Lynn]

Re: cuts off at wot

Ok this might sound stupid but just check it out and make sure your filter at the carb the small one is in right . if not the boat will run fine at idle and cruse good till you really put the hammer down then you will not get enough fuel...

 

[Bondo]

Re: cuts off at wot

it just started doing after the carb was rebuilt i also checked the high speed jets if they where clogging and they where

Ayuh,... Sounds like they're Still Plugged...