power valve ?

[bricklayer]

what are the symptons of a power valve failure holly 650 carb could be my problem? it was running fine after i fired it up for the first time, now when i start it it runs for a couple of seconds then falls flat and dosen't want to fire back up thanks tom

[firefighter3931]

A blown power valve will make it idle very rich.


Ron

[bricklayer]

ron would my engine still run with the throttle or will it fall flat and not run at all thanks  tom

[Cooter]

Depends on what year the carb was bought, as anything after like 1998 has built in power valve protection for cases like yours. Used to be, one backfire through the carb and you will be pulling the bowls off and replacing that power valve...

Could be a blown PV, but You need to look down the carb while cranking and see if there's fuel coming out of the float bowls over into the venturi..If it is, then I'd suspect a stuck float....BE CAREFUL and have a fire Ex. ready..One backfire and it's all over!!