Power Valves?

[Jeff Frigo]

How can you tell if the power valve in your carb. is blown? Does it run rich at an idle? Is there a way to test it out of the carb.?

[Hotfingrs]

Take it out of the metering block and suck on it. If the plunger goes in and out it's OK....

[427 S/O]

Jack's right...........

[69boss429]

Originally Posted by Hotfingrs

Take it out of the metering block and suck on it. If the plunger goes in and out it's OK....

Sucking on anything with gasoline on it is not a good idea!Besides it might have a pinhole and not react, There are testers you can hook to a vaccum pump,but for the price of a new valve its hardly worth buying a test setup. A simple rule of thumb,if you have had a backfire thriugh your carb,you most likely blew out the powervalve!

[Jeff Frigo]

Thanks guys, I will take it out today and test it, but what are the symptoms of a blown one while the car is running?

[ToyCollector]

I have never been able to get a carb to hold a tune with a blown power valve. If you had a backfire, and are chasing an even idle, I have always found it was a blown valve. As others have said, it is a cheap part. There is also a way to put a "ball bearing" in as a check valve to keep the power valve from blowing out during backfires.

[Carnut427]

When a power valve "blows", it's always open, causing a rough idle because of the extra fuel. The engine will run fine at other times. I've tried sucking on them as a test without success personally, so I'm resigned to replacing them if the idle is as described. Oh, by the way, a catalitic convertor will turn a nice cherry red because of the extra fuel. Spectre makes a power valve saver for around $10 or so, and Holley sells a 2-pack for around same price, although the Spectre unit is just a bit easier to install.

Dan