also the aprox. needle setting for the 91 is about 2 turns out each engine will vary of course,but like cambo just said there's some hot parts you won't want to touch.
all of my 91's are in cowls so its a little harder to come in contact with the engine, but I did get a nasty burn off the muffler a while back,if your engine is overheating it will usually die or loose power pretty dramaticly,and is quite noticable.