How to winterize the Honda 20 h.p. outboard

Each fall I must winterize all the outboard motors at Bow Narrows Camp. While not a difficult chore it does take quite a bit of time, especially when you consider the number of motors we must do. Our fishing boats are equipped with 20 h.p. Honda four-stroke engines.
I start by draining the engine oil by using a pump evacuator. This system sucks the oil right out of the engine through the dipstick tube.This is best done when the engine is still hot but it can be done with cold oil too.

Oil is pumped from engine

Now drain the lower unit by removing the bottom drain plug, then the top vent plug. This is vitally important because if water has infiltrated due to, say, fishing line being wound around the prop (like that ever happens!), then this water will freeze over the winter and break the lower unit.
This is thick, stinky stuff and when you do it in near-freezing temperatures the way I always do in the fall, will take about 10 minutes to finish draining. That means you can proceed with the next step and come back to this later. But before it is all drained out, take a look at the oil. It should be dark-coloured. If it is milky, then it has water in it. This could mean you need to get the prop seal replaced on this engine. It is best to have the unit pressure-tested to see if the seal is still good. Also pay attention to see if the oil contains metal filings. This means something has happened to the gear alignment, probably the result of striking a rock. There's nothing to do but get the gears replaced. Usually, however, the oil is just oil.
You should also take off and inspect the prop as well as the line-winder bushing on the prop shaft. If it has line on it, remove it, then put everything back. 

Oil drains from vent plug

Next, you will need to remove the cowling on the right side of the engine. It is held with five small screws. You will also need to remove the latch at the back of the engine. Take care not to lose the split ring that holds the entire clasp mechanism together. Unplug the engine vent and gasoline drain tubes from the cowling.

Remove tubes from cowling

You need to replace the oil filter. Unless the motor has been sitting on the rack for a long time, it will be full of oil so wedge a rag beneath it to catch most of the drips. Lube the rubber ring on the new filter before installing. Tighten by hand until snug.
Now fill the engine with one liter of 10W30 oil through the oil fill cap.
You now must drain all the gasoline from the engine. Even if you ran the motor dry before taking it out of the water, it will still have gasoline trapped in the fuel system. This could turn to varnish, thanks to today's ethanol-laced fuel, even if you use fuel stabilizer. So do this instead:
 Loosen the drain screw at the bottom of the carburetor . It will let any gas still in the carb drain out through the clear vent tube.Also, disconnect the fuel line that runs from the fuel pump to the vapour separator. There will be a great deal of fuel left in this. If it is clear, you can save this but if cloudy, it has water in it and must be discarded.
The fuel pump is the round object just to the right of my hand. The vapor separator is the jar-like object at the bottom right.

Gas is drained from water separator fuel line

Replace the fuel hose and reassemble the cowling.
By now the lower unit will have finished draining so fill the lower unit with 80-90w gear oil by filling from the bottom vent hole until oil appears in the top hole.
Wash off the entire cowling. Windex does a good job for this.
Store the engine upright over the winter.
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