Johnson HD-25 GREASE CHANGE Vent and drain screws are in same place on TD-20 motor.
part numbers on chart below will tell you the screws to remove. They are both flathead screws, the lower is a larger blade flathead.
#27,283 lower larger screw
#27,284 is the gasket (it's a bit thicker)
#27-283 is the upper screw and is a small flathead screw.
#27-284 is the gasket for the upper screw.
It's easy, and every outboard needs it's lower unit oil changed!
Start by locating the drain screws... drain the lower unit by removing the big screw #27,283 on the lower left. I also remove the water drain plug and gasket #43,300,580 (and #43,300,581 gasket) at the right on the pump housing (seen just right of center in picture and behind, to the left of the prop). AND I remove the upper FLATHEAD "vent plug" barely seen in this pic, upper left above the bolts that hold the lower unit together. see the pink arrows, it's up there.
this vent is in the same place on the TD-20 lower units. Once the drain screws are removed and the grease/oil is removed you can refill the lower unit. I have found it easiest to use one of the refill kits you can acquire from Kmart or WalMart for about $10. This kit includes a quart of 80W lower unit oil (not grease anymore) and a plunger pump you can screw into the top of the oil bottle. The hose has a screw thread affixed to the end that will screw into the lower drain hole. Screw the hose into the lower unit lower hole and pump the plunger until oil comes out of the top vent screw. the lower unit is refilled. NOTE: some old oil or grease may come out, that's okay. Replace the upper screw. this should make a tight enough seal to prevent losing too much (or any) oil from the lower unit lower screw hole as you remove the refilling tube from the lower screw hole. As quickly as possible, line up and replace the lower unit lower screw. Your lower unit is refilled and ready to go. If you use your motor a lot, rechange the lower unit oil after every 5 or 6 times out and for sure drain it at seasons end before storing. If your lower unit oil/grease has not been recently changed, if you acquired an oldtimer that has been sitting for any length of time, you may want to refill, run once and rechange the oil and re-run and rechange up to three or four times to be sure the lower unit is nice and cleaned up.
Now we will remove the tank before we can access the flywheel and then access the points, condensors, and coils, if you're going there... GAS TANK REMOVAL HD-25
