My 2008 Cub Cadet LT4510 the battery is strong and starter soloid kicks in and here spinning, but the engine does not turn over. I looked under the cover and the starter gear is engaged, but does not turn the engine. I hear high speed spiining.
If the engine will turn over by hand , as previously noted and the starter motor is spinning then the starter gear is most likely stripped or the flywheel has come loose.
Als as pre requested in the previous post, repair proceedures will depend upon what engine you have ad we need the full model numbers of the engine, and the mower ones won't hurt either.