heres my story outline version...
a. left ignition key on over weekend
b. did not realize ignition was left on when i went to start engine monday morning
c. used my 'quick start' jumper device(from costco)to start engine
d. drove to work ok,couple miles, generator light stayed off so charging seems to be working. but still not enough juice to start engine at end of day, so use quick start to start again.
e. get home, charge the battery, install battery and engine starts real easy. red generator light flickers on and off, never solid... i suspect fan belt is loose,so i try to tighten with new shims...crank over engine, generator light still flickers on and off
f. 3 wires on top of generator, two on trminal lugs on top are tight...one towards the fan housing on top of generator, maybe ground is loose...i tighten it down and generator light stays red....
g. any suggestions?...maybe the brushes? is there a way to trouble shoot? the engine is in a bus, so you know how hard it is to get to different parts....