I just got a .91fx recently too and the manual also said to open it 4 or 5 turns....open up the throttle all the....and then start it. And it worked like a dream to my surprise,but you had to keep the throttle wide open to supply enough air. It ran super rich(4-stoke mode as the manual called it). My manual also went into how and when to start leaning it etc. All that worked great too. The only thing that baffled me for awhile was how it wouldnt run at all at about 3 or 3 and a half turns out while playing with the throttle. But I realized it just wasnt getting enough air when I backed off the throttle like it did when the throttle was wide open to support that much fuel. Once I backed the needle down even more,it ran like a champ.

The 4-5 turns out method actually works great if you read the manual closely. In fact my new super tiger .91 tells you do pretty much the same thing now. So,just lean that baby out and you'll have a great engine. And if not......I'll give you $50 for it!!!!