When I had an Evinrude (same as Johnson) 2 cycle Sailmaster, made circa 1975, so not sure what may have changed, I did the following at the end of each season.
-- Take the ending home
-- Put engine on a wooden horse and ran the engine in a big trash can full of fresh water to flush it out
-- opened the upper and then lower drain plugs on the lower unit and drained all the oil out
-- used a small pump that connects to a bottle of lower unit oil and screwed the pump end into the lower hole of the lower unit. Pump in new 80 wt gear oil until it exits the upper hole. Screw the plugs back in place for both holes
-- take off the prop and grease the shaft with waterproof axle grease, replace prop
-- Open upper unit and remove plugs (x2)
-- Squirt in fogging oil, replace plugs, run engine in barrel until it stops (lots of smoke)
-- remove plugs and squirt in some more fogging oil, pull start cord to distribute.
-- clean and re-gap plugs and replace (or put in new plugs)
-- replace zinc anode under the cavitation plate, if need be
Hope this helps.
