I have a FMD I have been running for about five years now. When I go to start it there isn't enough of a connection to turn the engine over. I've had the battery checked, it is good and not that old. I've changed the main cables from the battery to the ground and selenoid.A year ago I was going through selenoids till I got one from what I take to be an original supplier for these tractors. I start the tractor by lifting the decompression lever to let it turn over and knock that down with a wrench and stars and runs fine. This summer haybineing I went to start the tractor and no start, not thinking I let the farmer offer a boost no go. He then towed me,he towed the tractor and haybine, when I let out on the clutch the tire of the major dragged rather than turn the engine over. We did this more than once till I remembered the decompression routine. Is there a compression lock happening or is it electrical? The electrical is to my mind in good shape.