It's probably the starter. I believe you have the 720 engine, it's not that hard to remove the starter. Get yourself a couple of small mirrors, 1/4" socket set, socket extensions and maybe a socket universal. You shouldn't need to take anything else off. Of course disconnect the battery first.
You're better off rebuilding the starter that you have, you can do it yourself or have a local shop do it. Lots of times they only need cleaning. Do not buy a 50.00 starter on EBay.
Lou