Re: What year?
I would want to do a compression test, if that is ok then start with new plugs, plug wires, and check distributer cap. A thorough carburator cleaning along with checking fuel pump, all fuel lines. Make sure the vent in the gas tank is operating properly. Sounds to me like it may have spark jumping to ground, or running lean in one of the cylinders...my first guess would be spark. Tho carbs get clogged very easily with 2 cycle mix. Just a Thought