ORIGINAL: Tired Old Man
I can candidly say that I've never, ever, had that problem. Even with weedeater conversions and an RCGF 26. If I had an engine that would not shut down with the idle trim I'd be doing some investigation and probably some repair work. It sure would not go to the field that way. Perhaps a different carb?
Lucky you. Anyway, I'm going to dig into my P-51/RCGF 26 that I've been unfortunate enough to have not shutdown with the idle trim and see if I can fix it. I suppose we can agree that yes, it would not be prudent to take it to the field until this is solved.