Are you getting into 4th gear yet? On a prior posting you were not shifting from 3rd due to the lack of required wiring to make the M-6 function properly.
Probably takes a good battery to run without a working generator. A marginal/poor battery may get you started after you charge it, but then not hold up for long to keep everything functional. Recharge, starts, but then same deal over again. It does sound like you have a generator problem, but the battery could contribute as well. Even with a working generator, and a good battery it may be necessary to bump the throttle up a bit before pulling the battery cable off.
Have you done a generator motoring test to check for generator output?