91 520H won't stay running.

[1990Onan520-H 15]

Hey all, long story short my 91 520-H won't run for more than 30 seconds. I checked the coil and it seems ok, checked the crank trigger and just get 12 volts. It never spiked to 1.5 when turning the engine over with the key on. Ran the same test on my 90 and got the spikes. Took the trigger off my 90 and put it on the 91... No dice. Still no 1.5v 12v spikes. Figured ok has to be the trigger ring and magnets, or the key snapped. Swapped the trigger ring, checked crank key, all was good. Still nothing. Now I'm at a loss. Any ideas as to why i am not getting the voltage fluctuation on my crank trigger? My 90 runs fine so I know these parts are good... other than the hole in the side of the block, but thats another story.