Fill Lower Unit for Winter?

[vettenuts]

I bought a boat to restore with a 65 Johnson 75hp on it. I drained the lower unit to make sure there was no water before winter (boat is outside and will see low temperatures). I have the new oil for the lower unit but since I found about a teaspoon of water in the lower unit am thinking new seals may be in order before this motor returns to duty. Since the oil isn't cheap I was thinking of not refilling the lower unit and leaving it empty over the winter months. Anyone ever leave the lower unit empty for the winter months?

[1fishbone]

I wouldn't leave it empty.
An empty case is apt to leave room for condensation.
After the oil drains away, and with all that moisture it starts to make rust...you saved $10 on oil but repairs will cost $$$...ummm?

You happen to forget to re-fill it ...you saved about $10 on oil but now need to rebuild the leg...ummm?

[lindy46]

Fill it up.

[wilde1j]

Empty is fine, in fact, it needs to be empty to leak test it. See shop manual for leak test procedure .... pressure (typically 15 psig max) and vacuum are applied. A good lower will hold some pressure for at least 45 minutes. Find leak source by submerging the LU in water and the bubbles will point to the leak. Choices are prop shaft, drive shaft, shift rod and the fill/drain screws excluding and housing cracks.

[Lostfisher]

If you leave it empty than make sure you put a tag on it as a reminder so you dont blow ur gears

[tx1961whaler]

You could just fill it up with regular car motor oil and drain it in the spring. Be sure to remember what's in it.

[Vic.S]

You could just fill it up with regular car motor oil and drain it in the spring. Be sure to remember what's in it.

This is what I would suggest.. cheap car engine oil ... the cheapest you can find.
But if the screws are refitted after draining there's not a lot of scope for moist air to enter and cause condensation even if it's left MT.

[samo_ott]

I would never leave an LU empty. But instead of engine oil go buy some 80W-90 gear oil. I can get a 4 litre jug here for $10-12 so it's a very cheap alternative and you can run it with it in it also. Although it does not have the outboard additives.

[boobie]

Never leave a L/U empty for a storage period. Fill it up with cheapest oil you can find and in the spring drain it, P&V check it and repair. You don't want any of the bearings to rust up.

[rjezuit]

Depends where you are storing it. In a dry, temperature controlled area? If so, there's enough oil that will cling to everything to stop rust. Take the plugs out, and leave them out, that way no possibility of forgetting. Tag the handle. no gear lube also. Most of it is aluminum, bronze and hardened steel it's been soaking ion oil all its life, as few months is not going to cause it to rust. . Rick

[boobie]

Over the years I've had customers who found water in their G/C in the fall of the year. They drained them and just left the plugs out. Come spring they brought in for repair and guess what?, G/C was locked up. Oil is cheaper than a G/C.

[lindy46]

Over the years I've had customers who found water in their G/C in the fall of the year. They drained them and just left the plugs out. Come spring they brought in for repair and guess what?, G/C was locked up. Oil is cheaper than a G/C.

Just had a 25hp johnson with a locked up gearcase. No oil in it. When I opened it up, everything was rusted. Couldn't even get the bearings off the propshaft, even after soaking in penetrating oil. Driveshaft was rusted to the pinion. Finally threw out the guts, cleaned up the case and replaced EVERYTHING inside.

[tony edwards]

anyone that tells you to leave it empty, must be in the business of rebuilding them. dont listen to it. put some oil in it because the remaining oil will dry off the parts. at least, use cheap engine oil. i will be glad to replace all your rusted bearings and gears next year....for a good price. get my meaning? cheap oil is a lot cheaper than a rebuild.