Drain lower unit

[Father's Day]

Hello Everyone
Wanted to change lower unit oil today, but all dealer were closed . Tonights going to be below freezing and I just took boat out of water. Question is should I drain lower unit and fill it when I get oil or leave it as is
Thanks

 

[PointedRose]

You just need to make sure the water drains from the engine for the winter (if not could damage parts when freezing). You do not have to worry about oil freezing, so leaving the lower unit full or empty in winter wouldn’t matter much, except that you don’t want to forget to refill it. So I would go ahead and refill it. You also don’t really need to do it annually. The benefit to changing LU oil is to ensure 1) there isn’t water leaking into the LU (exhibited by milky oil) or 2) excessive gear grinding exhibited by metal shavings in the discharged oil.

 

[seasick]

If there is no water in LU oil, it can wait till spring. It should not ne stored empty. That is asking for trouble since the internals can rust.
If in the worst case, there is water in the LU oil, the unit should be serviced but it if can't, it should be drained and refilled and serviced again later.
For peace of mind, one approach is to drain a small amount of oil, maybe a few ounces into a clean pan, or foil tray and see how the oil looks. If you see a milky mixture or whitish streaks, the oil has water.
The water can freeze and if enough water, the LU casing can crack.

 

[Father's Day]

If there is no water in LU oil, it can wait till spring. It should not ne stored empty. That is asking for trouble since the internals can rust.
If in the worst case, there is water in the LU oil, the unit should be serviced but it if can't, it should be drained and refilled and serviced again later.
For peace of mind, one approach is to drain a small amount of oil, maybe a few ounces into a clean pan, or foil tray and see how the oil looks. If you see a milky mixture or whitish streaks, the oil has water.
The water can freeze and if enough water, the LU casing can crack.

Thanks guys I always change it every year because you never know if there is water in there. That was my concern ill make sure I find it somewhere tomorrow

 

[SkunkBoat]

Just crack the drain loose til something drips out.
If it has sat for any time, any water will be at the bottom.
If water drips out or milky oil drips out, tighten it back and take it for new seals asap.
Do that now! Don't wait til spring to find out you need it serviced.

If the oil looks good, it can wait til spring.... but ... I try to do oil & gear oil asap, before closing up for the winter.
IMO you change gear oil once a year. Its called MAINTENANCE.
ALWAYS change the Gaskets on the Fill/Drain screws.. The are not reusable. Get them before you start.
I always have a spare screw just in case it gets messed up removing it.
Use a GIANT flat screwdriver.

You can get 80W90 or SAE90 GL5 gear oil at any Auto store or Walmart or West Marine.


Never drain oil and wait til spring to fill it. That is the makings of a sad story.

 

[Father's Day]

Just crack the drain loose til something drips out.
If it has sat for any time, any water will be at the bottom.
If water drips out or milky oil drips out, tighten it back and take it for new seals asap.
Do that now! Don't wait til spring to find out you need it serviced.

If the oil looks good, it can wait til spring.... but ... I try to do oil & gear oil asap, before closing up for the winter.
IMO you change gear oil once a year. Its called MAINTENANCE.
ALWAYS change the Gaskets on the Fill/Drain screws.. The are not reusable. Get them before you start.
I always have a spare screw just in case it gets messed up removing it.
Use a GIANT flat screwdriver.

You can get 80W90 or SAE90 GL5 gear oil at any Auto store or Walmart or West Marine.


Never drain oil and wait til spring to fill it. That is the makings of a sad story.

Thanks for your reply

 

[Sardinia306Canyon]

Never drain oil and wait til spring to fill it. That is the makings of a sad story.

Yep,
same for non freezing areas where cracking the housing is not a issue as water in LU is a bad thing in any case.

I usually do all the maintenance in autumn when i pull the boats as i don't see a sense of storing the engine

• with old and maybe aggressive or corroding oil inside motor and LU
• not freshly greased and maybe water/humidity in tilt and steering tubes
• pulling the lower unit to check for binding or stuck driveshaft
• old spark plugs

some of the above does not really matter for storage except that for example spark plugs may show problems and it's generally better if problems are discovered in autumn than just before splashing her in spring/summer.
It is arguable better to change impeller just before new season, however i see no problem to have new impeller installed 6 month before. I usually don't install the LU or have it screwed on but just a few turns to tighten in spring.

Chris