I need to replace the belt on a Sear's 22" lawnmower. I do not have the owner's manual.
I would appreciate guidance on how to replace.

Thanks and have a wonderful day!

Remove the spark plug since you are dealing around the blade area. Remove the blade and blade adapter with pulley. Or see if you can just remove the blade and rotate the pulley and pry the belt off. Remove the cover of the belt, and remove from that pulley.

My Sears 22' self propelled belt change was a pia. This is how I did it:

1: Pull spark splug
2: Tilt mover up on the opposite side of carburetor so that oil doesn't flow in. (or you can just drain the oil)
3: Pull blade off
4: Slide blade holding collar off. (Mine was tight and I had to use a wedge.
5: I finally had to remove 3 engine bolts and lift engine out to remove collar. Couldn't seem to get the right angle for the wedge.
6: Pull cover off and remove old belt and replace it with the new one
7: Clean shaft, wd 40 and put color back on
8: Set engine back in mower and tighten up bolts.
9: Slip belt on the wheel drive pulley>
10: Put blade back on and tighten and away you go.

Note: I expected that the mower would move faster with a new belt but it didn't but the wheels would now continue to drive even uphill and through rough terrain now.

Hope this helps!