Welcome to JUST ANSWER small engines, let me try to help you !!
Check compression, and if it is over 100 psi, the compression release is not working.
What is the model number of the engine ? example(NNN) NNN-NNNNB1
There is no pressure release, if it is the engine I think it is , the release is on the camshaft gear. You can try adjusting the valves. Intake at .003 to .005 in. and .005 to .007 inch on exhaust.
You can get compression gage at autozone, they may even rent them, Or harbor freight.
Try the valves first, remove the OHV cover, four bolts and the valves will be exposed.
No, starter is not going to be issue, you know the starter spins engine with spark plug out. So starter matches flywheel.