BBC Idle is circa 970-1000 RPM in park Drops to around 810-820 in drive Cruise RPM ranges between 1700 - 2100 and WOT I only ever take it up to 5000 After acceleration in drive, but with my foot off the gas pedal, rpm slowly drops to around 1300 and rarely goes below. I'm fouling plugs in 10 mins. Badly fouled. Carb is an 4500 style Quickfuel Fuel pressure 3 psi floats are only 1/3rd up on the sight bowl idle screws only 1/2 a turn out I have reduced the transition slot and even lowered the jet sizes by 6 sizes I have also triple checked the pump shot I've replaced return springs. Somehow someway the carb keeps feeding fuel to the engine when my foot is off the gas. Any thoughts ?
It's an 1150 but the engine has had a lot of work done to it including higher compression and bigger cam. Something has changed as it ran fine up until recently
As any 'modern' Holley carb based carb, verify the metering blocks are properly sealing against the main body. Gaskets are correct for your application. Next would be to verify that the blocks/body are still flat and not tweaked/warped. Otherwise, check out this link... http://www.clubcobra.com/forums/holley-tuning/147135-fix-rich-running-quick-fuel.html
OK think I have solved it...fired it up and watched carb closely under load then idle. Rear secondary pump shot was leaking fuel between the nozzle and the screw. Go to tighten it and guess what...stripped. I suspect this has been ******* fuel into the carb. Out to get a helical kit tomorrow. Probably need to resent all my changes once I fix that
The Jalopy Journal
