I wouldn't worry about the little puff of blue at startup especially a cold startup. As long as you keep the oil level good it will keep going for a long time yet. Mine keeps going and shows no signs of loosing power.craneway said:Thanks broken2 I did put the wrong switch in according to my local source and smoked my solid state ignition. I am now looking for a replacement. Dont know much about the hh120. Wondering if it is worth the rebuild. It ran but puffed a little blue smoke at startup. Also, was wondering what year it really is. The motor/tractor. mod.#hh120-120045B Ser#847 08051 The tractor mod# is MF12 Ser# 1446 506 523 A part # for the solid state ignition modual would also be helpful. Thanks friends.