Ihave a suz,ltf-250,94mod. starts easy runs out great but if i let idle for a few,builds up gas and stalls out,I figgure its a gas buildup as black smoke comes out exhaust on startup,only time i see any smoke at all.Can any of the experts explain the carb,and tell me if there any adjustments,?Dont know anything bout carbs,but not afraid to learn!?THANKS, PAUL

 

How long has it been since the air filter was cleaned and oiled? As they get dirty, they restrict more air, which leads to rich mixtures.
How old is the gas in the tank?
If thats ok, then theres a mixture screw, for the idle circuit, and going in is leaner. Im not sure exactly where it is, but is either on the side or on the bottom of the carb. It could simply be out too far. I think about 1 1/2 turns out from lightly bottomed is a good place to start.