Yet another MC2100 situation
88 YJ 4.2 A/T HEI ignition module, ford dist cap, base and rotor, MC2100 from early 80's Ford van(currently the one with the problem)
mixture leans out/engine stumbles during initial acceleration from any speed. (verified by an air/fuel ratio gauge).
situation and what I've done:
replaced my old junkyard MC2100 with a "new" junkyard MC2100. Got home and rebuilt it. old carb had #52 jets. New one has #48. It has a new 6.5 power valve. Installed carb. I DID adjust the accelerator pump linkage in each possible configuration, and test drove in each possible configuration. it IS squirting fuel when cycled. I tried to richen the mixture. Timing is at 10 BTDC (changed nothing besides the carb itself...well I adjusted the mixture, of course, using a vac gauge). All this and no change in performance. Old carb was replaced due to a vac leak at the throttle shaft, wasn't worth fixing, but ran better than it does now. Again, the only change i made was the carb. I'm thinking blown accelerator pump...but it's new as of two days ago. Any ideas?