Re: lower unit rebuild 97 force 120
It is a Merc lower unit and you will need a large spanner to remove the threaded retaining rings behind the prop (if it has one--some merc propshaft carriers are simply held with two allen head capscrews. You will also need a spanner to remove the retaining ring under the water pump. A couple of breaker bars and a torque wrench are necessary to remove and replace the pinion. AND You will need something to hold the drive shaft while you "break" the pinion nut. If you change bearings or gears you must shim the lower unit again.
It is not an easy job but if you are a competent shade tree mechanic you can do it. If you are just replacing seals, it is an easier job and does not require breakers or torque wrenches.
