Stutter in acceleration
I have a 77 CJ5 with a 304 V-8. It has the stock motorcraft carburetor, hedman headers, K&N airfilter, T150 manual transmission, stock dana 20 Transfer case, etc. It has been converted to a manual choke. The Motorcraft 2100 2 bbl carburetor seems to be in perfect condition. Everything seems to be in adjustment, and working fine. When the engine is below 1000rpms, if you step on the gas with any force, the engine stutters and stumbles (irregardless of what grade gas it is running). If you stomp on the gas, it occasionally backfires. Over 1000rpms, it runs like a clock. If I pull the choke out and then step on the gas, the problem is solved…but by smelling the exhaust, it is clear that the engine is running way too rich. And pulling the choke usually means that the engine won’t drop below 1000rpms at idle, anyhow. My first guess was to check the accelerator pump, the timing, and the mixture, but all seem to be fine. Any other ideas on what could be wrong? I have read a great deal about Jacobs ignitions (along with its various counterparts, DUI, etc.). Would such an aftermarket ignition possibly cure this problem?