2003 Polaris Scrambler 50-90 Sportsman 90 Predator 90 Service Manual, Page 58Get this manual
FUEL SYSTEMCARBURETION
CARBURETOR SPECIFICATIONS
The carburetor has been updated to accommodate the choke systemThe oil check valve has higher resistance spec to eliminate leaking oil into the carbScrambler 50 Cutaway Air Screw NeedleSeat Pilot Jet Main Jet EClip 3.0 12 turn out from lightly seated 1.2 25 75 #3 from top
CAUTION: main jet that is too small will cause lean operating condition resulting in serious engine damage
HIGH ALTITUDE OPERATION
2003 Youth ATVs have been tested to 12,000 ft above sea level to assure satisfactory performanceNo jetting or clutching changes are required for high altitude operation
CARBURETOR JETTING
IMPORTANT: The following guidelines must be followed when establishing main jet setting: 1Select the lowest anticipated temperature at which the machine will be operated2Determine the lowest approximate altitude at which the machine will be operated3Select the correct main jet from the chart in the specifications sectionCAUTION: main jet that is too small will cause lean operating condition resulting in serious engine damageSelect the correct main jet carefully for elevation and temperature according to the charts in the Specifications section or in the Owner's Safety and Maintenance Manual for each particular model