Re: Testing Stator & Rectifier
The small non regulated rectifiers can be tested by following Joe Reeves' instructions on the Engine FAQs board but I know of no way of easily testing the regulated ones as fitted to a 140 looper.
The stator coil could be tested for continuity. It'll have a fairly low resistance but you wont detect shorted turns. The AC output going to the rectifier (yellow wires) could be checked. Can't quote a figure but you should get well over 12volts once the revs are increased.