just put a new starter drive and starter relay on my 76 shovel also had the starter check out shop said it was in good shape not draging or anything now when i hit the starter botton it hangs up keeps going till i pull cable off starter drive never ran across this before can anyone help

 

This problem usually starts with a discharged battery Happened to me several times to the point of leaving the seat loose to get at the bat connections when the starter did not release Good bat / charging system good to go

 

had same trouble after changing clutch hub - this worked for me - loosen all bolts on outer primary and move it up and to rear - give it a try