I have a bad lean sneeze on this motor that i brought back from the dead (froze up). I have cleaned and rebuilt the carb 2x, including under welch plug & w/carb kit, replaced coils, points, condensers, plugs, wires, shut off wires & switch, fuel lines, thermostat, impeller, lower unit oil, & cleaned fuel pump. It stays running on one plug when one wire is pulled, I've set spark advance so just as butterfly begins to open roller is at the mark on the cam, spark jumps a 1/4" gap (but no more) with a tester. Fuel pump works fine pumping into a jar.Motor runs fine at mid to high speed but wont idle; just dies if I try to lower throttle. Compression is a little low (55 & 59). Might come up with a decarb but its not running well enough to try that yet. I've not yet pulled the head, saving that for last resort so as not to risk breaking off a bolt. Based on research here I think it may be an air leak in the crankcase. How do I confirm that and find the leak? Where is a leak likely to occur?
