650 proform carb leak down troubles

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johnnycuda

johnnycuda

JohnnyCuda's 68
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Hey all when ever i start the car cold overnight she starts right up.
After i take a ride and start it lets say any where from 10 minutes to 2 hour later she does not start right up.
I must hold the gas 1/8 to 1/4 down and it takes a good 7-10 secs before she kicks over.
I noticed the front see threw bowl emptyies out alittle but i do not see it leaking down looking inside the carb? and it does not leak on the manifold. this carb is fairly new and it was over $500 bucks.
Is there a gasket i can change inside the front bowl to help the leak down? Any advice would be appreiciated hate to have to buy a new carb.
 
Either the power valve has a small leak or the intake is boiling the gas and is causing it to evaporate causing the low fuel level.Does fuel come out of the boosters when hot by it,s self?Does it run rich when you get into it?You may need to block off the heat cross over to stop the intake from heating up and causing the fuel boiling,mrmopartech
 
Mrmopartech said:
Either the power valve has a small leak or the intake is boiling the gas and is causing it to evaporate causing the low fuel level.Does fuel come out of the boosters when hot by it,s self?Does it run rich when you get into it?You may need to block off the heat cross over to stop the intake from heating up and causing the fuel boiling,mrmopartech
Click to expand...

No fuel out the boosters, not running rich only on restart it seems.
the car runs great just has issue starting right up. and you can definetly notive the fuel level drops threw the sight glass.
 
Sounds like heat soak, and the fuel is boiling out. Try an insulated carb gasket (Edelbrock part number 9265 or 9266 if you have a square bore carb) before thinking about spending money on a new carb.
 
Yep try a phenolic spacer, should take care of that problem if there are no other underlying issues.
 
i would take the bowls off and check that the power valve is installed correctly..that the gasket is seat under it...and look for a pitch gasket....regardless if it is new or not..it was assemble by a human being..
 
AAR,onto something. Does the power valve style,match the gasket?.
 
I put a spacer with mine and it made a huge difference on restart.. I suspect this would of happened to me aswell with any carb.. However with that said im very happy with Proform.
 

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I already have a spacer???
SOMBODY ELSE SAID I SHOULD TRY LOWERING THE FLOAT?
 
What kind of spacer exactly? Leave the floats where they are unless the fuel level is too high.
 
It's a black phenolic spacer.
I changed the needle and seats still haas the same issue.
Going to check the power valve next i guess,
I also lowered the fuel pressure with a stock pump.

UOP said:
What kind of spacer exactly? Leave the floats where they are unless the fuel level is too high.
Click to expand...
 
Well i got rid of the Proform 650 and put on an Edebrock 600. froma member here new in the box by the way!
Runs fantastic!!!
Starts after being warm no problem!
Before it took a good 10 secs to turn over when warm.
Happy days on to the next issue!!!
gear change to 3:23 or 55 or new front bumper, or heater box install or rear spring swap!
 
Did you ever check the power valve? I just had the exact same problem with a new Holley 750HP I installed and when I took it apart to check it out I found the power valve gasket wasn't sealing. Installed a new gasket and it starts fine every time now. IMO you took a step back going to an Edelbrock
 
No i didn't try the power valve that was next.
I really wanted an electric choke on it anyway.
I'm happy with my descision. starts fine now.
It ran too rich with that carb anyway.

fishy68 said:
Did you ever check the power valve? I just had the exact same problem with a new Holley 750HP I installed and when I took it apart to check it out I found the power valve gasket wasn't sealing. Installed a new gasket and it starts fine every time now. IMO you took a step back going to an Edelbrock
Click to expand...
 
johnnycuda said:
No i didn't try the power valve that was next.
I really wanted an electric choke on it anyway.
I'm happy with my descision. starts fine now.
It ran too rich with that carb anyway.
Click to expand...

It probably ran too rich because the power valve or gasket was leaking past. That was another issue with mine. As soon as I replaced the gasket it leaned out over 1/2 point according to my A/F gauge. Glad your happy with your new one. That's all that really matters. If you want to sell that Quick Fuel carb PM me
 
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