hello i have a 1996 yamaha timberwolf that i recently purchased. I rebuilt the carb and just changed the oil with valvoline 10w-40 atv oil and replaced oil filter. plus put in ngk plug. the thing is that now it smokes a little more than before and my spark plug is fouling. also it won't idle well and sometimes just revs itself up. any help will be appreciated. thanks in advance.

 

Sounds like a rich idle jet setting with an air intake leak.

Tighten the carb boots clean the airfilter and adjust the idle jet to 2 turns out.

 

hello thanks for response i am kind of new to owning a 4-wheeler is the idle the big **** withe knurl on the side of carburetor or the screw under the carb which i believe is the pilot air mixture? also when i rebuild the carb, is their supposed to be an o-ring or something on the the screw under the carb it keeps slipping out on its on if i ride it 4 a while. any help will be appreciated.