your tuning may be way off so you could try retuning it here is a simple way i also posted it in the faq thread

ccw means turn the screw counter clockwise
cw means turn the screw clockwise

lsn-ccw richens and cw leans
hsn-cw leans and ccw richens
idle-cw opens the gap and ccw closes the gap

Set air gap of throttle 1.5 mm,(idle screw), HSN Cw til it bottoms out then 3 1/2 turn CCW. LSN Flush with the throttle housing + 1 turn cw. Try to start, will be runnin really rich, if it starts. Turn down idle speed, then adjust HSN cw til you have good acceleration to idle. if your idle speed rises, turn it down. May have to do a couple times. Last adjustment LSN, turn cw slowly til idle speed starts to rise. when it rises you're running lean, turn it CCW till idle speed just drops. Blip the throttle you should be acceleration ok with some smoke coming from the muffler.Lean the HSN 1/8 turn CW till your satisfied.

i also posted a pic of the motor