I can get this old atv to crank but it idles very rough and dies. If I give some throttle it seems to smooth out. Sounds to me like the idle mixture is wrong. How do I correct this?
Thanks

 

Ahead of the float bowl on the front side is where the fuel air mixture screw is located. turn it clockwise until it is lightly seated. back it out 1 1/2 to 2 turns. Start the unit and let it idle with the choke off. Turn the screw in until the engine begins to stammer, counting turns, turn it out slowly, the engine should smoothen out, keep turning out until it stammers again. Set the screw in half the turns you just counted and that should be the engines sweet spot. If this cannot be obtained the float valve is worn or the o-ring and or washer at the end of the fuel mixture screw is bad or missing. (install a new spark plug before adjusting the carb as described)

-----gimpster-----

 

fisrt thing i would do before all that, wich is good advice is take the carb out and cleasn the intire thing, float slide all of it, than play with the idle stuff.

 

There is one other possiblity that I have ran into many many times on these old models, they require the slide needle and slide needle jet to be replaced, this is very common on these old ones. Try what Gimp says first, if you can achieve a smooth idle that way, then you will most likely have to replace the slide needle.
I would think if the float needle wasnt seating you would have fuel leaking out the overflow of the carb. Also, if after trying what Gimp says on the air/fuel screw, and it doesnt clear up, watch the exhaust very closely while idling, it will probably be puffing just a littel black smoke, another indication of a worn slide needle and jet.

 

I finally took the carb off and cleaned it as good as I could. I saw how the idle control works and when I put it back together gas was pooring our ot the overflow tube. I cranked it and adjusted the idle and it runs very well and after running it for a few minutes the gas stopped coming out of the overflow tube.
Thanks for the advice.