Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
When it was working, would it hold up a load, or did it leak down? Do all other functions work ok? Hydrostat transmission? Front end loader? My first thought is that the seals on the three point piston have failed and the piston needs a new seal ring.
You say operating lever does not move? As in stuck?
The three point housing needs to be removed. Are you prepared to do that? I would remove the housing, that gives access to the inner linkage and will let you check the piston seals on the lift cylinder piston.
No, the seals would not keep the lever from moving, but to get to the linkage, you are going to have it off, and I would check the piston.
The whole top of the three point comes off as a unit.
Here is link above.
Here is link to the linkage and the parts book.
I see question is still open, did you get to remove the cover yet?
Yes it does involve a lot of work!