So after lots of wire/circuit chasing with no service manual I think I have narrowed it down to one of the micro-switches on the accelerator assembly. This would be the switch that sends power to the forward/reverse selector. I have bypassed every other switch (one at a time) with the same results. However if I take and put battery voltage directly to the switch the contacts instantly engage and stay engaged till I put the selector back in neutral.

I have a new switch ordered and hopefully this fixes the problem otherwise the next step is to call in a mechanic or wrecker, jury is still out on that decision.