Flywheel extender?

[Golfdad75]

Tonight my flywheel pulley for my FWC came off with the shaft. The shaft (extender?) that it fits on has two set screws that hold it in place. The flywheel shaft has two pins coming out and the extender slides over that. My question is two fold
1) is all that holds the flywheel on to the main shaft are these set screws?
2) I can't seem to get the belt tight enough. Would the belt tension have something to do with the pulley sliding off? Should I try to get a longer bolt? (i have a bolt on the freshwater pump that pushes against the bell housing)
Any suggestions? Tonight we got in by my friend hold a hammer against the pulley not allowing it to slide off.
Thanks guys

[Golfdad75]

Well here is what I found.

The extender I had was pressed on. The sleeve that is used to form a tight fit had worn out. Evidence by the thin metal shavings. Moyer Marine sells a PTO shaft extender that fits behind the flywheel bolts. No amount of cranking on the set screws was gonna make that extender stay on. I have ordered the part from Ken and I am good to go.