Onan Aux Issue

[Rich Biebel]

Ok David that is an old gas unit..

Has points and condenser and a coil and all that has to be good.
The engine has a low oil pressure switch. That could be your problem. Some were 2 terminal and close with pressure. That completes the 12v power for the ignition. If it has a 2 wire switch you can jump it and see if it runs with it jumped out. The switch is mounted above the oil filter on most of the old flathead Onan engines...

The switch can be tested with an ohmmeter. Whatever it reads engine off......it should be the opposite running.

N/O = normally open.....and that should close running
N/C = normally closed...and that should open running

2 wire closes or opens across the 2 terminals
1 wire closes or opens to the switches body....which will be grounded at the engine when it is screwed in.