randy carlson

Fired up my fresh engines last night, had a few backfires before first runs, one engine running good, other acts very rich- from idle all the way up to 3000 would a blown power valve cause this ? If I remember correctly I should be able to look in carb and see extra fuel pouring in? first time around Holley's. Randy

kennyo

Very possible on older holleys. Newer ones had anti backfire check balls I believe.

Griff

Sounds like a blown powervalve to me also. Also check your fuel bowl levels. They could be set to high and are dripping fuel.

BDiggity

i had same symptoms on my carbs after i had a big backfire. ended up having 2 blown powervalves. after we got them changed, everything ran great.

ENFORCER24

If you have fresh engines in the boat its probably time to put a couple of kits in the carbs anyways , even the cheap kit for my holley had a pair of 6.5 power valves , even tho my carb only uses 1 power valve

ezstriper

while idling you should not see any fuel dripping in, if you do ck float level(site plug side of bowl) or trash in needle & seat, if thats ok, pull the fuel bowls & metering blocks, look at the diapham of the power valve, if it's wet it's blown, may have 1 or 2 if it did blow and if its a older carb by a power valve protection kit and install with the new power valves. set float level so fuel right at bottom site plug, good luck, Rob

RunninHotRacing163.1

Sounds like a blown powervalve to me also. check your fuel bowl levels. Sounds like they are set to high and are dripping fuel.

cigrocket

iTrader: (3)

Power valve, I had this on an HP500. Easy fix

randy carlson

Thanks Guys, swapped carbs last night to verify, it is carb, pulled it apart this morning blown power valve and trash in secondary needle seat. put a kit in it and heading home to see if I cant get her in the lake a bit this afternoon Randy

Griff

Set the float levels with the boat in the water. The angle of the carb changes with it in the water compaired to the trailer.