Carb./ Power Valve Help
 

I have a 750 HP holley and its drinking gas bad, It acks like the floats are stuck but there not theres no gas dripping down the carb,And it wont idle right unless i rev it up to 3000 RPMS, Could it be a bad power vavle? PLEASE ANY ADVICE, THANK YOU

Re: Carb./ Power Valve Help
 

Yes, it could be a bad power valve. It could also be too much fuel pressure, or the mixture screws way out of adjustment.

Has it backfired through the carb recently?

Re: Carb./ Power Valve Help
 

Thanks for the reply, I replaced the power valves and check air/fuel mixture, Fuel pressure is at 7 pounds, Thanks CAR9FAN

Re: Carb./ Power Valve Help
 

Turn your fuel pressure down to 5 psi and see if it makes a difference. 7 is too high anyway.


Mechanical secondaries or vacuum?

Both the primaries and the secondaries just barely dribble gas out the sight plugs when you remove them, with the engine running, right?

Is it pig rich at idle, or when you get on it? Does it smoke? Is the choke wired open or removed?

Re: Carb./ Power Valve Help
 

Yes it is pig rich, I have a good 750 df/dp but it does not have the 4 corner air screws like the one iam working on, But my carb. has a Pro Form Main Body and works great i just wanted to try this one because its got HP tag on it, I put my front and back needle valves in it and the only way it will run if i rev it up to 2500- 3000 RPMs, There is fuel dripping down from the secondalys, I gave up and put mine back on, I will see if i can find someone to work on it, Thanks for the help, CAR9FAN

Re: Carb./ Power Valve Help
 

Check the o-ring for a slight tear.

I rebuild Holley's. let me know if you can't find anyone local.

Re: Carb./ Power Valve Help
 

I once had a similar problem with fuel dripping out the secondaries. It was the needle and seat not shutting off the gas to the secondary fuel float bowl. That should show up in the sight glass or plug as a high fuel level that doesn't respond to float adjustment. When you replaced the needle valves, did you mean the needle and seats or the idle adjustment screws?

Rev

Re: Carb./ Power Valve Help
 

Thanks Guys, I replaced the needle and seats/ the part that adjust,s the floats and still no luck, I have a freind hes said he knows someone that can fix it, Thanks Again, CAR9FAN