Hello, My 6250 NW-2 is messing with my mind. Sometimes when I first run it that day, all it does is sit there and buzz no matter how many times I cycle the E-unit. Now, if I give it a nudge, it works ok for the rest of the time I'm using it. At other times when I slow it down and it stops moving but there is still some voltage going to it (the lights are still lit) and then give it more voltage to get it moving again it just sits there buzzing. At this time I can cycle the E-unit and it runs ok. I've cleaned the commutator, brushes, and E-unit. The engine has been greased and oiled. Any help will be greatly appreciated. Bossman