It will not start as long as the starter is engaged.
Been like that from the day I bought it new.
Replaced stock battery with DEKA automobile size.
Replaced oil with less vicious oil- can't remember weight.
To start, crank for few seconds and stop. If it starts- fine.
If not, repeat.
Took it to dealer soon after I bought it and dealer could find no problem.
After it starts it runs fine.
I have a thought, I might be off but I think that unit has a fuel solenoid on the carb that shuts off fuel at shut down. My thinking is that in the start position the solenoid is not opening . Just something to check .