I believe its the same carb as on a grizz. The mixture screw (and this only adjusts the mixture for the idle circuit, .....mid and full throttle are changed by changing needles and jets), is located just forward, of the float bowl on the bottom side of carb. Not the easiest to get at. You might want to just change it while the motor is cold, and then test drive it...to keep from buring your hand. A number 4 flat driver bit, fits the slotted screw pretty good. Home Dump has them. Just use your fingers on the bit...there isnt alot of resistance to turning. There may or may not be a piece of plastic or metal covering the counterbore the slotted screw sits in. If theres a cover, flick it off. The mixture screw fine tunes the pilot jet. The range is anywhere from about 2 turns out from bottom, to about 4 turns out. If the motor needs more than 4 turns out from bottom..the pilot jet needs to be bigger. Turning out (unscrewing) is richer...in is leaner.
Heres an article on jetting you might find help ful.jetting and troubleshooting