Refill lower unit lube - Real dumb question time

Hal380

Cadet
Joined
Oct 22, 2010
Messages
9
Good moring all;

I am a new owner. I have been reading about winterizing and other motor care issues. When it comes to draining and refilling the lower unit lube, I just cant picture the process.

Here's what I understand.

1 - with motor in verticle position open the two SLOTED screws. DO NOT TOUCH THE PHILLIPS HEAD SCREW. Ok got that.

2 - Oil drains out -bottom hole - makes sense.

3- (the part that doesnt make sense) start at the drain hole (bottom) and fill the lube oil unti it comes out the top hole.

4- Quick like a bunny screw in the botton drain screw before all the lube runs out.

Queston: is the real way you do it - drain the oll while motor is in verticle position and then raise motor to horizontal and then fill oil til it runs out of top hole?

If that is the way to do it, then forgive this very litteral minded German Irishman. I have not receive my manual yet so I am just wondering around the forums looking for instructins on various issues.

Regards to all

Hal
 

Bob_VT

Moderator & Unofficial iBoats Historian
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May 19, 2001
Messages
26,065
Re: Refill lower unit lube - Real dumb question time

Good Morning. ;)

Not a dumb Question.

Fill from the bottom until it comes out the top hole and replace the TOP screw first (while the gear lube filler is still plugging the bottom hole........ then remove the gear oil (tube or whatever you used) and quickly replace the lower screw.

Just like when you play with a straw in a glass....... the vacuum created when you re-install the top screw first will help hold in the oil.
 

Bob_VT

Moderator & Unofficial iBoats Historian
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26,065
Re: Refill lower unit lube - Real dumb question time

Oh yeah......all done with the engine vertical both drain and fill
 

Hal380

Cadet
Joined
Oct 22, 2010
Messages
9
Re: Refill lower unit lube - Real dumb question time

Thanks friends;

Sounds like fun but will follow instructions.

Quick question. Why not just fill from top after you put in the bottom plug?

Regards

Hal
 

eavega

Lieutenant
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Apr 29, 2008
Messages
1,377
Re: Refill lower unit lube - Real dumb question time

Filling from the bottom hole allows oil to push the air in the gear case through the vent hole and ensures you filled the gear case completely with oil rather than having a hidden air pocket in there. You could do it the other way around, but then you would have to have a way for the air to escape through the same hole you are trying to fill with oil.

-E
 

robert graham

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Apr 16, 2009
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6,908
Re: Refill lower unit lube - Real dumb question time

This is really an easy proceedure, not very messy, takes about 5 or 10 minutes. A little bit of clean lower unit oil on your fingers is good for your skin! Make sure your drain/vent plugs have new/good washers/gaskets and tighten then down good! Good Luck!
 

glengold

Petty Officer 1st Class
Joined
Feb 24, 2010
Messages
310
Re: Refill lower unit lube - Real dumb question time

i might add.... you should check to make sure there isn't already a worn out seal in the recessed part. I recently changed mine and the previous owner had put a new seal on top of a worn out one because he didn't notice it in the recessed part. this allowed water to enter the LU.
 

bonzoscott

Senior Chief Petty Officer
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Jul 26, 2008
Messages
745
Re: Refill lower unit lube - Real dumb question time

If you fill from the top hole with the bottom plug in, it will trap air in the case. When the lube settles, you will not have the correct level of lube. It will then burn your gears/case up.
 

Fed

Commander
Joined
Apr 1, 2010
Messages
2,457
Re: Refill lower unit lube - Real dumb question time

FWIW Mercury used to make a pump type bottle that had a hose/screw connection to fill with, much easier than squeeze bottles with tapered tips. Not sure if the plug threads are the same for various outboards though.
 

5150abf

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Aug 12, 2007
Messages
5,808
Re: Refill lower unit lube - Real dumb question time

A tip if you are using the quart bottles, I get 2 and fill the one I am going to use all the way to the top, it makes it easier to get it filled.

Some of it is going to leak out no matter how fast you are with the screw so don't worry about that either.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Refill lower unit lube - Real dumb question time

With the bottom (drain) screw in place, you cannot "force" lube into the now sealed lower unit. Forcing fluid in requires that air be forced out. Using an oil can for example, you could accomplish the task, however it would take forever. Just believe the millions of outboard/I/O owners who have done this for many decades.
 
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