Well, found the problem with the tach.
The last "mechanic" that worked on the motor stuck the ring terminal from the rectifier/regulator to the grounding location instead of the solenoid stud.
I would have never thought anything about it till I showed Daddy the route the wires were run. Quickly he said "that eyelet looks too big for that stud".
Sure nuff after going thru every wireing diagram with no help for termination, the BRP parts number for that said "ring terminal,solenoid".