[1Quik7D]

Just rebuilt a holley 600cfm, vac. secondaries and it seems to be fine except when I hit the gas. I'm getting backfire through the carb. I just bolted it back on, so I havent had time to adjust the mixture or floats. Maybe that's the problem, but I thought I'd check since I wont get back to it until tomorrow. TIA for any help.

 

[Bob B.]

Did you replace the power valve?

 

[1Quik7D]

yep, with the one in the rebuild kit. Fired up just fine, but when I hit the gas it will spit up through the card once and a while.

 

[70_FathomBlueMalibu]

did you change the timing any? It could be a bit retarded or possibly your accelerator pump is out of adjustment on the carb. Maybe some of the carb gurus will step in on this one.

------------------
Justin Wray
Fathom Blue 1970 Malibu daily driver
1/8th mile best of 8.95 on street tires. 1/4 mile equivalent is 13.96
Still tuning for 8.30 in the 1/8th or 12.99 in the 1/4. Whichever comes first.....

 

[BradleyBergstrom]

Same thing happened to me after rebuilding. If I am not mistaken, carb backfire is attributed to a too lean condition. Try letting each of your two fuel mixture screws out 1/4 turn. Any one else agree?