If it turns over, that leave 4 things that could be wrong with it. It could be a fuel delivery issue, simple fix as a carb cleaning or replacement. It could have no spark, either an electrical issue grounding the coil or a bad ignition coil. or it could have no compression.
which could be the piston rings are totally shot,or a valve stuck open. 4th, could just be a sheared flywheel key throwing off ignition timing.