What will a blown power valve do?

[el paso mod 19]

I haven't taken carb apart yet, but I think I may have blown a power valve. Put new carb on two races ago. Had problems getting motor fired and it backfired once. Then this last weekend it backfired again as I was going past flag stand. Motor will not pull rpms. 7150 rpms with a 648 gear. Should turn 7700-7800. Pulled plugs at track and they were a little on the wet side. Be gentle with me; I'm not a motor man at all. LOL

[cheaterleaddog]

A blown power valve will sound blubbery or fat at idle. If you take metering block off and it is wet behind block power valve is bad. I would recommend changing plugs also.

[el paso mod 19]

Does both metering blocks have a power valve? Will both probably be blown?

[cheaterleaddog]

yes and yes Not guarantying that if dry it is not leaking but if wet it is leaking. There is a tester for them but power valves are cheap just replace. They do make high flow power valves.

[let-r-eat]

You can tell by taking the sight plug out of the bowl and filling the bowl up to the sight plug hole by fillng through the bowl vent. The float level should stay steady and the fuel shouldn't disappear.A blown powervalve empties the bowl of the carburetor. You can do this on the bench.