Having trouble diagnosing a carb problem with a WCFB carb. Problem: The engine runs rich, rough at idle of around 750-800RPM, and the passenger side primary nozzle (booster) dribbles/spits fuel out at idle. It will also do it at lower idle speeds also. Both primary and secondary boosters do appear to atomize the fuel normally when the engine is speeded up. Background on the engine and carb: Engine: rebuilt 327 with a mild high energy type cam, 4 spd trans. Ignition timing is around 15 @ idle and changing it around will affect idle quality but has no affect on the booster spitting fuel. Right now the timing is set to where the engine idles the best and has the highest vacuum which is around 11 lbs. Total timing is not known at this time and will be addressed after the carb issue is resolved. The engine runs fine anywhere off idle speed. Carb: Supposed to be the original carb restored by a reputable company. Its all pretty, re-plated, clean etc, but runs like crap. Casting numbers on the air horn, main body and throttle body (base) all come out to 1963. Jets: Primary 120-165 Secondary 120-222 Metering rods are the same and don't appear to be bent or damaged. Metering rod link stays down at idle and is adjusted properly and raises as the throttle is opened. Both idle mixture screws are around 1 turn out. Adjusting them does affect the idle quality, but does not have any affect on the spitting fuel from the booster at idle. Fuel pressure is around 4.5-5 lbs while running. Float levels are within specs and has Daytona style needles and seats. What I have done: Disassembled the carb, it appeared quite clean, inspected it, cleaned it. Blew out all the passages with compressed and and also squirted brake clean through them with the nozzle tip and blowed them out again. All the passages appear to be clear. The main body is re-plated and appears to have new led plugs installed in the passages and I did not remove them while cleaning. Reassembled the carb and decided to lower the primary float level a tad more, just incase the float level is causing the issue. The only thing I really saw was the base to main body screws were pretty loose. Put it back on the engine and it still does the same thing. Maybe some of you guys might have some insight on what's going on with this carb. I have built a number of WCFBs in my time and really have never and problems with them. They are not very complicated. Any help from you guys will be much appreciated. Bill
The Jalopy Journal
