Holly Doulbe Pumber Leaking

[DaveCameron]

Hi

Have just purchased a jetboat with a 350chev with a holly double pumper on it. When at idle the fuel seems to drip from the jets down the barrel. We have put new gaskets between the float bowl and the barrel, made it idle a little better but we still have the leaking. I just read something vague about the power valve could be the problem. I am new to big engines the biggest I have worked on before was a Honda XR600. Thanks

 

[ivymike]

Are the floats floating? That's the first idea that comes to my mind - that a float may be bad, causing the bowl to over-fill. I've not got the most experience with carbs though...

 

[DaveCameron]

Yes. We have checked the float levels. Not over full.

 

[TheBlacksmith]

Holleys are noteworthy for blowing out the power valve if the engine backfires. They have a new design powervalve, don't know if it backfits. Some aftermarkets (Mr. Gasket) have kits. Are you sure the float levels are correct? Holleys should have the final level set with the engine idling and the level plugs pulled (new Holleys have clear plugs - in response to the obvious fire hazard). Any dry setting with the bowls removed is just preliminary.

Blacksmith

 

[sbc]

Sounds like the pwr valve. It doesn't sound like
this is a marine carb. as all marine Holleys Iv'e
seen are vacuum secondary units. There are a lot
of subtle but IMPORTANT differences between the
marine & automotive units.