On the back end of the engine lokk down inside the hull and you should see a plastic cover held on with 2 plastic wing nuts, remove those wings nuts and you should see the carbon ring seal on the drive shaft and the PTO plate...you should be able to turn the PTO plate by hand (thus turning the driveline and pistons, etc).
And remove your spark plugs, this will make it easy (no compression), , often the pto has grease on it, so place a shop rag on it, and that will do the trick.