TOPIC: need help

just picked up a homelite 55 turns over fine, good spark, plugs are in the right order, carbs are clean, but it will only back fire.

I cant figure it out

Any progress getting it straightened out? If you have fuel and air, look closely at the ignition system. Check the coil, and distributor components including the points, rotor, condensor, and rotor. Also check the distributor base. There is an nylon key that locks it to the cam shaft. Had one of those keys break once. Hopefully this advise isn't too basic for you.