Issue with g9 starter generator and engine

I recently purchased a G9 yamaha gas cart, which apparently had an issue with the starter generator. It also had a issue of the forward /reverse switch being reversed so forward was reverse and vice versa. After buying it and charging the battery, the cart started and drove fine apart from the forward reverse switch being around the wrong way . But after lifting the rear end and testing the charging output i found it to be only charging at 8 volts. After checking the wiring diagram for the cart, i noticed the starter generator was in fact incorrectly wired, (supply + to A2, link between f1 and f2 and - to a1 ) instead of ( supply+ to f2, link between a2 and f1 and - to a2). After finding this i thought i had solved my charging issue so i changed to the correct wiring which also corrected the forward/ reverse switch. Only problem is now the starter generator runs correctly but the engine will not start. To check, i swapped the wiring back to how it was and the engine started straight away, changed it back to correct wiring and once again the engine wouldn't start.

I can't figure it out as i can't see any correlation with the starter generator wiring and the engine not starting , any ideas or help would be much appreciated