1995 Big Bear quad running rich on idle
 

Just bought this atv, from an old landlord at work , sat in shed for 8 years , only 750 km on clock so mechanically new , will not idle
Mixture screw nearest motor on carb , makes no difference which position it is in , is there an air screw for this model carb ' mukuni BTM'
I have blown all airways out with compressed air , no difference, any suggestions out there:)