1. Replace all the gas in the tank and floatbowl -clean out the piliot jet with an ultra-fine piece of wire (one strand from speaker wire works great):YOU SHOULD REJET HERE, BUT IF YOU DON'T, OK. 2. Replace the air filter: if it is deteriorating, it will clog your jets 3. Replace the plug 4. Drain the vent hose near the swing arm (a 'squeezy' vent) 5. Cut the end off the plug wire 1", and re-attach plug cap (fresh connection) 6. Clean off ground wire for coil under tank (this corrodes all the time) 7. Remove and clean kill switch, and it's connectors (short/open problems) 8. Make sure the choke is off 9. Make sure the fuel screw is out 1.5 turns NOW start it, with no choke (I assume you know the ritual). Remember, it takes 10 FULL MINUTES AT IDLE before it is warmed up. Anything else, and it will sputter. With stock jetting, it can still hesitate, lurch, and sputter intermitently, but not if you roll-on the throttle.