Whats with this lower unit lube?

scrawnyronny

Seaman Apprentice
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Jul 19, 2009
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I found a greasy spot down the side of the lower unit. Decided that the drain/vent screw washers and lube needed to be changed. Found no washer on the vent screw and 2 on the drain screw. Besides the obvious issue with the washers, what can be learned based on the appearance of this....stuff? Doesn't look anything like the replacement. Keep in mind my nubishness.( is that a word?) Haven't had this rig that long and I'm here to learn.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
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5,125
Re: Whats with this lower unit lube?

It's not too bad but it looks like some water has gotten in it. I'd replace it, put 1 washer on each screw and then check it again in 10-20 hours of use.
 

5150abf

Vice Admiral
Joined
Aug 12, 2007
Messages
5,808
Re: Whats with this lower unit lube?

Ya, that dosn't look bad considering you only had one washer on it.

I will loosen my lower screw now and then just to check, let just a little oil come out and you know you are okay, if water comes out you know there is a problem.

Hopefully the chunks were in the pan before you started.
 

Lion hunter

Lieutenant Commander
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Apr 9, 2005
Messages
1,529
Re: Whats with this lower unit lube?

I don't see nothing to worry about. It don't take much water to turn the oil milky. But if there is oil there...it's still working.

Lower unit oil has emulsifiers that bind water so that as long as there is more oil in the unit than water, water doesn't come in contact with moving parts. It's not a real strong bond in that if it sits without agitation it will seperate. Usually takes several days to fully seperate. That is why it's good practice to drain and refill LU after end of season. Once it seperates there will be parts in contact with pure water which will rust and freeze.
 

scrawnyronny

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Jul 19, 2009
Messages
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Re: Whats with this lower unit lube?

Yes, the chunks were in the pan before draining so no problem there. When I drained it there was no obvious water coming out so I guess I was alright there as well. Don't really have any idea as to when this was last changed but I will make it a yearly pre-freeze routine from here on out if thats what is required. I was just alittle shocked at its appearance since I'd never seen this before. Saw a neighbor change his once and it was bluish.
 

Vic.S

Rear Admiral
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May 4, 2004
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4,718
Re: Whats with this lower unit lube?

Saw a neighbor change his once and it was bluish
Colour is just whatever the manufacturer cares to make it. Without any added colouring the oil is a straw colour.

The important thing is that it should remain "clear and bright" cloudiness or milkiness is a sign that it is getting water in. A small amount of fresh water you can live with until the end of the season, then get it vacuum and pressure tested and replace whichever seals are leaking. Or just replace the whole lot anyway. I'd worry more if its salt water.

Change the oil every 100 hours of operation or every year, whichever is soonest
 

samo_ott

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Jun 18, 2006
Messages
5,125
Re: Whats with this lower unit lube?

I run many old engines and most LU's take on water. I have gotten to the point where I don't really care anymore... Just use good LU oil that works better if there's water in it and change at the end of every season. And I have not had an LU fail yet...
 

scrawnyronny

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Re: Whats with this lower unit lube?

Just fresh water here Vic. I don't think a guy can get any futher away from salt water than where I'm at. :D Thanks
 

samo_ott

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5,125
Re: Whats with this lower unit lube?

Fargo? haha Good point! Unless you test it in a salt water pool! :)
 

scrawnyronny

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Joined
Jul 19, 2009
Messages
47
Re: Whats with this lower unit lube?

So I do my shopping at Mills Fleet Farm. (a mans department store) They have the quicksilver brand.(blue in color) I'm guessing this will be alright? Color of the lube doesn't seem to be an issue, just the right weight and electric shift/manual shift specific?
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,899
Re: Whats with this lower unit lube?

The cheaper oils such as Coastal(Autozone) 80/90w do not have antifoaming agents in them, the gears aerate the oil causing it to turn "baby poo yellow". I have seen small motors brought in for leaks that passes pressure/vac tests and oil change cured the problem. I only use Volvo synthetic in all my customer units.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: Whats with this lower unit lube?

Change the oil with a quality oil. Use new washers on the screws. I use the hex drive screws in my lower unit (I just don't like the slotted ones) personal opinion though. Run it for 10 + hours and drain a bit to check color to original.
 

scrawnyronny

Seaman Apprentice
Joined
Jul 19, 2009
Messages
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Re: Whats with this lower unit lube?

Well, I never expected this many response to such a dopey questions on my part and I just wanna say thank you to all who have replied. You can bet as I venture further into the intricacies of owning my own boat there will be more meatheaded questions to follow.:)
 

Lion hunter

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Apr 9, 2005
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Re: Whats with this lower unit lube?

This is great forum and we all have meathead questions on things we don't understand, there will always be someone here to answer them. Better to ask a question than make a expensive mistake.
 
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