8N charging problem

simonmeridew · May 12, 2013

My 51 8N isn't charging. Wiring is intact and continuity is there. Ammeter shows slight movement to the neg side when the key is turned on, but starting the engine doesn't resolve this like it used to do. The contacts don't appear stuck in the regulator, as far as I can see. Are there brushes in the generator that could be worn? How do I get at whatever could be wrong?
simonmeridew

Dollar Bill · May 14, 2013

1. First, polarize it by jumpering BAT to ARM, then restart.

2. If no charge on ammeter, at 1000 rpm, then jump field post to ground, if charge jumps up... V/R bad - Replace.

3. If still no charge, leave that jumpered and now jump BAT and ARM, if charge comes up then cutout and possibly field circuit is bad. Again, replace V/R.

Note: The full field test makes the gen charge at max so do not leave it jumpered for longer than it takes to read the ammeter.

4. If that provides no charge, then you need to motor it with the engine off. If still no charge do a motor test... Remove belt, jumper BAT to ARM, and ground the FLD. Gen should spin if it is good.