Holley Carb Issue

Went to the Canyon yesterday, Have flow scan installed on boat, have noticed that the port engine at 3200 rpms appeared to burn 2 gallons per hour more at this speed, at lower rpms fuel burn was the same, have heard a pop or two from the port carb in the past , noticed while on the return trip my port fuel consumption jumped to 24 to 26 gallons per hour while starboard stayed at 10 gph. PRAYED that it was a gage issue, got back to fuel up gage was right(ouch) I have heard that if the engine backfired it would mess up the power valve? I have also heard that it may be the accelerator pump? Plan on pulling the Carb and haveing it rebuilt, just seeing if anyone else had the same issue or do I need to look at something else?

Re: Holley Carb Issue

What engines are these Holley carbs attached to? Full model numbers would sure help.

Re: Holley Carb Issue

Don S said:

What engines are these Holley carbs attached to? Full model numbers would sure help.

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1985 volvo, 5.7 chevys, 308 hours

Re: Holley Carb Issue

When were the carbs last rebuilt? Holley power valves were known for blowing as a result of backfiring through the carb, but Holley started installing a check ball and seat starting in 1992 to prevent this. But since both the power valve and accelerator pump diaphram are easy to access and check to replace, that is definitely where I would start.

Re: Holley Carb Issue

Send it back to Holley. Holley rebuilds AND tests their carburetors. Not all places do flow tests. One way or the other, that will answer the carburetor question. Mine got took out by water in the fuel tank. They gotterdid for me. I've slept and boated much easier since.

Re: Holley Carb Issue

Boat Ran great, ran in 6 foot swells at 3100rpms, 9 gallons per hour per engine at 19 to 20 knots