power valve

What happends when your power valve goes out in a holley carburator??? Like what does the motor do?

Goes rich - the vacuum chamber that makes the valve work is exposed to manifold vacuum, so any leaking fuel will go straight into the engine. The engine does not have to be running - if the gasket or diaphragm is leaking, the front bowl will slowly empty into the engine until the fuel level is below the power valve. That would be a bad leak. Most problems with PVs are with the gasket, not the valve.

Gee Mr. Texan,..

Such a breath of fresh air.

There has to be 50 persons at this forum that refuse to beleive that a carburetor used to have a power valve, and what the symptoms were.

Looks like we have someone here who beleives in basic auto analysis.
Just keep going.

Wm.

I believe in powe valves, but figure this one out. New Holley 750, and had the same problem with the old Holley. Have set the secondary idle, changed power valves (idles at 8-9 inches vac) using a 4.5 power valve, and the car just smells so rich it kills you. Starts up and it smells sweet, runs a while and it gets rich.
I actually dialed my fuel pres back to 6, and have dropped the bowl levels to where they dont run fuel out the peepers.

Also, car has a big of a flat spot when cruising along at sped and you step down on it, it goes flat or hesitates. Holley said I had done all I could, with the cam its got I may have to drill holes in the secondary butterflies? The only thing I have not been able to do is mess with the Idle Feed Restrictors.