Pull the bowl and clean everything well with brake clean. The pilot jet is ~.012" (slightly bigger diameter than a human hair) and plugs easily. Check your float height and drop while you have it apart. Set the float height at .880" and drop @ 1.050."
Start the engine (kart on the ground) and raise the idle rpm to 2200 with the idle adjuster screw (directly under the slide.)
Next, turn the air bleed adjuster screw (one closest to the air filter) out (counterclockwise) to lean the engine at idle until the engine increases to it's highest rpm at idle. If turning the air bleed adjuster screw out didn't raise the rpm, then turn it in until you find the highest idle rpm.
Make sure that the engine doesn't run high enough rpm to engage the clutch and get away from you.
Finally, turn the idle screw out (counterclockwise) until the idle is once again at 2200.
See if that doesn't fix your problems.
There may be other issues (clutch locking up, throttle cable or slide/needle not properly assembled, fuel pump, fuel tank/lines/filter/shut-off valve, vent in tank cap, etc.) but this will rule out the majority of typical problems.
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Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cut
z
www.CarlsonMotorsports.com
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33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com