You should apply hot ungrounded battery voltage to the gennys ARM post and "ground" to the gennys case/frame NOTTTTTTTT the FLD post
!!!!!!!!!!!!!!!!!!
If the gennys mounting is solid absent paint etc its case frame provides the "ground" so hot UNgrounded battery voltage to the ARM post
with belt removed should make it spin, see below. For POS ground the case/frame is to the batteries POS (even though called "ground") and
the battery NEG provides the hot UNgrounded voltage source
NOTE to be safe you should first Polarize the genny by using a jumper wire to momentarily flash jump from BAT over to GEN/ARM on a cutout
relay or a voltage regulator and you should get a small spark
NOTE on manual Low High light switch charge control system with a Cutout Relay (NOT a full fledged Voltage regulator) if theres no charge
it may be the Low High light switch has a poor ground. Theres a wire from the Gennys FLD post up to the switch where it gets its ground. if
that wires missing or the switch isnt grounded well NO CHARGE even if the genny itself is okay
NOTE BOTH the genny and cutout relay plus the Low High switch alllllll need good grounds...
FYI heres how to Motor Test a Generator:
MOTOR TEST. You can Motor test the Gen. If its grounded and you remove the belt and apply hot battery voltage direct to its ARM Post and
have the Field Post dead grounded to case/frame, it should motor n run well (Armature n Brushes and Commutator likely okay). Then, if you
next remove the Fields ground and it speeds up some, the Fields probably good. If it passes BOTH those tests, it should charge, and if not,
it may be a wiring or battery or grounding problem. The hot battery voltage may be taken off the VR's BAT terminal or the starter post or
the battery itself for this test.
FULL FIELD TEST: TO DETERMINE IF ITS A GEN OR VR OR CUTOUT RELAY PROBLEM Your M has a Cutout Relay, see below for test
5. a) VOLTAGE REGULATOR SYSTEM: With the tractor running, temporarily ground the Gens Field post to case. If she charges then but NOT
otherwise, the VR may be bad, or a wires missing from VR's Field post to the Field terminal on the VR, or the VR isn’t well grounded.
b) IF IT’S A CUTOUT RELAY SYSTEM and she charges only if you dead ground the Field but NOT otherwise, its either a bad switch or the switch
isn’t well grounded or else the wires bad or open from the Gens Field post up to the switch. INSURE THAT GOOD SWITCH GROUND AND WIRING
6. If she still don’t charge, leave the Field grounded and jump a wire across from the VR or Cutout Relays BAT terminal over to its GEN
terminal (jump by passes the cutout relay) and see if she charges. If then but not otherwise, a VR's cutout relay isn’t working correct
(maybe points burned/carboned) or a Cutout Relays NOT working or not wired correct.
7. With the 2 steps above, you have basically by passed the VR or Cutout relays functions, so if she still don’t charge, you're left with a
bad battery or wiring or the Gen itself.
NOTE if its charging at fast RPM running a 6 volt battery voltage should rise from say 6.3 (full charged) to at least 6.5 up to near 7
volts. If battery voltage never rises nor an ammeter read + charging amps, either the Genny or Relay or Low High switch isn't working or
not well grounded
See my Troubleshooting Procedure linked below for more info
https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=2060825
John T
John Ts Troubleshooting