As per the OS instruction manual, the first starting should be done at 2-2 1/2 turns out. My .91 runs about 1 1/2 turns and is set a few clicks rich.
I broke mine in with a 13x8 and found it runs great with a 14x8 and 15x6. after the problems my friend and I had with a used .91 FX I was considering
not buyng one but I haven't had any problems with mine. And my friends used 91 problems were all due to a airleak in the needle valve. We both run
our engines on their side with jett in cowl mufflers. http://www.jettengineering.com we have both also used slimline mufflers and found that if you plug
one of the exhaust outlets like some people reccomend the engine does not perform well.