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Author Topic:   Power valve blowout?
posted May 25, 2004 07:15 PM
From my experience w/ ablown power valve it will idle fine but pop and sputter at high rpm's probally b/c its not opening causing fuel starvation.

posted May 26, 2004 07:02 AM
The carb will be excessively rich at idle, since fuel will be passing through the blown PV diaphram itself and into the cavity behind it and directly into the intake thru the vacuum hole in the bottom of the cavity behind the metering block.
So, NO, the car will not idle properly, it will not accelerate properly, and performance throughout will be poor.


posted May 27, 2004 11:23 PM
The one time my powervalve was blown, the only time I could tell was at high rpm's. This was a rodchester carb, maybe it was not blown but when I changed it the problem stopped, who knows.

posted May 28, 2004 06:43 AM
KP. Is there any real way to tell if a power valve is blown once you take it out? Also does the advertised power valve blowout preventer really work...

posted May 29, 2004 06:58 AM
The quickest way (although not the most health-conscious) is to stick the large end in your mouth and "create a vacuum" on it. If the valve shuts, and holds shut without leaking air thru, then it is fine. Now, the REAL way is to use a special PV testing tool with a vacuum guage so you can test exactly what pressure it closes/opens at.
Sometimes, you can see evidence of the PV leaking, as there will be fuel stains or raw fuel in the cavity behind the PV in the main body of the carb. There never should be fuel in there.
As for the PV blowout protection "kit", yes, they work, or at least seem to cut back a lot on PV failures.


[This message has been edited by KPLugnut (edited May 29, 2004).]

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