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Holley power valve-check ball

5K views 4 replies 4 participants last post by  lg1969 
#1 ·
Hello guys, need a little help here, I was doing some cleaning on my carb and replacing some leaking gaskets, while cleaning the throttle body I noticed the check ball, that thing that I always forget that it's there, but my questions is: How to test if the check ball it's working properly?

I had problems with a blown power valve before, while closing the mixture screws the engine didn't die, I just had to replace it with a new PV, but right now the problem started again and the engine didn't backfire

Can anyone help me diagnose or test the power valve and the check ball?
All help is appreciated
 
#2 ·
Do you own a vacuum pump? If so , go to the store & buy a pack of those suction cop hangers that your wife plasters to the windows to "display" stuff..take the hook off , drill a hole in the "base" part of the cup , push the pointed adapter from your vacuum pump in the hole & viola , you have a power valve checker...as to your reference to a "check ball" where in the throttle body is it located?

dave
 
#4 ·
It's a one way check valve. It allows vacuum to the PV but prevents pressure from reaching it. Basically using compressed air you can put pressure to the intake side of the check valve to see that it stops (most of) the air pressure you apply. There may be some leakage, not to worry. Air should pass freely in the opposite direction. Clean it w/canned carb spray.

The PV can be checked as outlined above. If the PV is old or has been wet and dried out several times and/or is old, just replace it.
 
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