1. Disconnect the cables from the battery(s).
2. Disconnect the control cables (throttle to starboard and gear selector to port), battery cables, exhaust
hose, fuel line
and wiring. If your motor has the alternator kit remove that as well. (The lighter you can make it, the better.)
3. Remove the 4 bolts and 2 nuts that hold the motor on. There are 2 bolts and one nut each on port and starboard sides. The nuts are furthest aft. This can all be reached from the front side of the motor. There are no bolts to remove on the aft side of the motor. The nut on the starboard side is the toughest one to get but it can be done with a regular box end wrench and some patience. (either 7/16" or 1/2", I don''t recall)
4. Gently pry the motor up off the adaptor plate with a large screwdriver or small pry bar. Go slowly and think about what you are prying against, work from side to side. Once the seal is broken the work starts.
5. Lift the motor straight up and off the drive shaft (about 2 inches). (This is the part where you discover everything you did not disconnect) Set the motor aside and be careful it doesn''t tip over and break something. Next, the gear selector linkage has to be disconnected from the vertical rod that disappears down into the lower unit. Be careful not to break the locking tab as you will need to reuse it.
6. Now you can get at the bolts holding the adaptor plate. I don''t recall how many there are but they are easy to get at. Remove these and pry up the adaptor plate. (There is one nut and it may be buried in gooey carbon so be sure to locate and remove it before prying)
7. Now you can see the black plastic housing that encloses the impeller, held on by 4 small bolts. Remove these and slide the plastic housing up and off the drive shaft.
8. Now you can grab the drive shaft and pull it up and out, with the impeller on it. Don''t worry, the drive shaft slides back into place easily.
9. Replace the impeller (lube it up with something such as Fluid Film) and then reassemble everything. Be sure the throttle linkage is aligned while lowering the motor back onto the drive shaft.
Be sure to keep track of the various gaskets and seals. Replace as necessary. The O-rings can be acquired at any hydraulic shop. The seal in the plastic housing might be obtained from a bearing dealer. Gaskets must be ordered from an OMC dealer if you can find one that will bother. If you are really good you can cut new gaskets yourself, but make sure the thickness is correct. I was able to reuse mine. Be sure to use high quality gasket adhesive upon reassembly as leaks will let water into the boat. I recommend Permatex''s "Right Stuff". Very expensive but good.
There will be a lot of carbon on the adaptor plate, this will need to be scraped out and cleaned up.
By the way, you CAN''T do this while the boat is in the water. There will be nothing to stop water from entering unless you want to swim under and somehow plug the water intake on the bottom of the lower unit and then swim under and remove the plug when finished.
Since the boat is out this is also a good time to change the oil in the lower unit, clean up the motor, lubricate all linkages and change the water pump
anode (which is screwed into the adaptor plate.
Hope this helps.
ArthurJohn. Contact me offline and I can give you Andy''s email so you can contact him directly.