1999 Polaris SLH, SLTH, SLX, SLTX, PRO785 Factory Service Manual, Page 103Get this manual
FUEL SYSTEMCARBURETION Carburetor RemovalMikuni Low Speed Mixture Screw Adjustment (Mikuni and Keihin) NOTE: Synchronize carburetors and adjust idle speed precisely with tachometer (in the water) before adjusting low speed mixture screwsTurn each low speed screw in clockwise to lightly seat, then back each out the specified number of turnsSee charts at the beginning of this sectionNOTE: This is base setting onlyFinal adjustment must be made by warming the engine to operating temperature, and adjusting low speed screws in (to lean) or out (to rich en) mixture until smooth idle and good throttle response is obtained