Farmboy, I just finished pulling the engine and fuel tank then reinstalled on my 853, what fishfiles says is right. I pressure washed the inside of the tank and installed new rubber bushings and plugs, along with a new fuel sender and fuel lines. Pulling the engine is really not all that bad, a little tricky on the reinstall. Watch the fuel sender, it sticks up about 1/2 inch and the hydro drive will break it off if your not carefull. I also replace all hard-to-get-to radiator hoses.
As the engine and hydro drive hangs from the engine hoist, it tilts down, it's much easier if it's level. I used a come-along and welded a bolt on top of the engine hoist, then used it to hook one end of the come-along, the other end ran over the engine and down to the hydro drive. I cranked until everything was level.
I have a standard style engine hoist and with limited space to lift the engine, I removed the 'hook' from the hoist and replaced it with a thick wall 2x2 square tubing about 15 inches long, drilled to accept the bolt. then used my power band saw to cut a v-notch in the end of the 2x2 to accept the chain. Don't want it to slip off...