I blew a power valve on my Holley 3310. I have the replacement valve, but I cannot find instructions on how to replace it. I even bought a Holley book but it does not tell how to replace the power valve. Can someone give me a link or a simple how-to for this proceedure? Thanks, Keith

Pull the front bowl off, 4 screws. Behind the float bowl is a block which is 1/2" thick, in the block is the power valve. It takes a 1" wrench , do not over tighten it.

Dave

Just so I know for future, how did u know u blew the pwr valve? What are the symptoms? Thanks.

The car backfired through the carb when we first started it after the rebuild. If the PCV valve is connected, the car shuts down like the key was turned off. I emailed Holley they said that it was a deffinate symptom of a blown power valve. When the PCV is disconnected, the car runs great.

The main symptom I've always seen is the car running pig fat at idle (if it will even run) and low throttle situations. It's probably burning your eyes out as it's dumping fuel into the carb throat before it can use it.

PCV Positive crankcase ventilation??? What does this have to do with a power valve.
Just because a car backfires doesn't mean the power valve is damaged. Most carbs have an anti backfire check valve so a backfire won't hurt them.

I've never yet seen a blown power valve on a Holley that didn't seem to be the result of advanced age deteriorating the diaphragm.

More-or-less a non-issue to my way of thinking.

OK, what is your best guess as to why it won't run with the vacuum hooked up to the PCV? The techs at Holley are the one's who said it was the power valve. The carb was old of course but I had it rebuilt. Like I said, the car runs excellant (not rich) when the PCV is disconnected.

what started this deal? out of the clear blue or was something else changed? you've been driving it OK everyday and one morning you go out and it's doing this? classic signs of blown PV are rich idle and the ability to seat both idle mix screws without killing the engine.

OK, what is your best guess as to why it won't run with the vacuum hooked up to the PCV?
If you add additional air through the PCV system; and the engine runs bad--I'd be expecting the engine to be WAY TOO LEAN.

Now, this assumes that you don't have so much raw gasoline in the oil that you're richening the mixture via the pcv system. Not common--but possible.

I would richen the mixture screws some; plug in the pcv system like it's supposed to be, and then final-tune the mixture.

Just for giggles--is the PCV valve defective so that it isn't restricting/metering the air at idle?