Gear Oil(lower unit)

[ishmael]

Does gear oil go bad with time? The stuff in my lower unit is maybe eight years old, but isn't near the hours for a change. The manual doesn't say anything about changing it just for age.

[uncas]

Ish!
What is the color of the oil in it now?
If it is whitish, you may have some water/moisture in it.
I replaced mine in my old seagull last fall. It had a certain chalky look to it.

[Mrleft8]

You have an outboard?

[ishmael]

It's a five horse Nissan kicker, Doug.

I'll stick a finger in it and look to see if it's contaminated, Jamie.

So, it doesn't go bad with the years?

[uncas]

Doug
If you are referring tome, I've got two. An old seagull which puts along just fine and a 2.0 HP which is basically brand new.

Ish...that is all you can do. Again, it is whitish in color. As if there are a lot of air bubbles in it.
At least, that is what I found in mine.
Just drained it out, let it sit overnight to get everything out, put in new and plugged it up.
Gear oil, the amount I needed didn't cost much.

[Kim Whitmyre]

I've got a 5hp Nissan as well: came with the boat. I drained the lower unit prior to use because the oil looked like a chocolate milkshake. Simple to do, and no doubt better to have more oil than water for the gears. . .:)

[uncas]

Ish
Kim described the consistency better than I did.
Hey, if it doesn't look like oil, change it!

ps...you might want to replace the "O" ring on the plug when you do this especially if moisture is getting in there.

[Memphis Mike]

It's a pretty common sense question, Jack. Change it at least once a year just to be on the safe side.

Better to do in the fall to remove any moisture before storage. But if your's hasn't been changed in 8 years, I'd do it now. Neglecting an outboard motor is the cause of most folks problems on the water.

It's inexpensive and easy to do yourself.

[Erasmus B Dragon]

Neglecting an outboard motor is the cause of most folks problems on the water.

Awl dis thyme ah thowt it wuz neglektin a spowse. Sew I gess ah wont have no trubel cuz ah aint got won o dem infurnal masheenz.

[BrianW]

Can it be checked, without basically draining it anyhow?

[uncas]

Brian
Can't see why not.

[BrianW]

Guess it's just a quirk of mine. :)

I don't know the exact drain/fill set up on a 5hp Nissan. All the ones I've drained have 2 plugs, a lower plug to drain and fill thru, and an upper plug to let you know when the gearcase is full, and perhaps to allow air to escape while filling.

If left sitting for too long, the water and oil could seperate. If all the water settles to the bottom, and your only pulling the top plug to check the quality of the oil, it may look fine. That could be fixed by simply running the engine before checking.

One could pull the bottom plug, and see if water comes out first, but how many times can you do that before you need to refill anyhow. :)

You advice on replacing the o-ring/gasket on the plug is spot on!

[High C]

It's old. Change it.

[ishmael]

Thanks, gents. I'll change it out.

Now I have to find a fitting that will screw into the lower plug hole. Hm.

[Stiletto]

You may find that gear oil comes in a sqeezable tube with a conical spout just made for the job. As Brian said, in at the lower hole until it comes out the top.

[BrianW]

You may find that gear oil comes in a sqeezable tube with a conical spout just made for the job. As Brian said, in at the lower hole until it comes out the top.

Yep, or even NAPA has the lower unit oil change kits, and the various adapters for the plug. At least around here they do, as there isn't a Waste Marine.

[Peter Malcolm Jardine]

One of the reason oil should be changed, regardless of hours is that it contains stabilizers that enhance viscosity, and reduce corrosion. These chemical additives break down even if the engine is not being used. Once a year if you have very few hours running would be probably overkill, but oil is cheap.

[Memphis Mike]

Jack, buy two tubes of oil. You don't need no fitting. Uncap both tubes beforehand so you'll have both hands free to do the job.

If the first one empties and does not squirt oil through the top, insert the second one and squeeze until it does.

My motor is a lot bigger than yours and it takes a tube and a half to fill it up.

[uncas]

For some reason, my seagull only has one plug.
Hence, I left the unit upside down for the night to drain all of the old oil out.
And no, I have no idea why there is only one plug! One would think there would be 2!

[Stiletto]

British sense of economy!;)

[pipefitter]

I was always under the impression that lower unit lube was the same as 90 weight gear lube used in cars in disguise. It definitely has the same smell as hypoid.If you get it on your clothes you might as well toss them because the smell stays there forever.

[Stiletto]

You may be right, I vaguely recall seeing EP90 on the container sometime in the past.

[ishmael]

This manual calls for SAE 80.

I seem to recall the odor of the heavy gear oils is due to them being scented with garlic oil. Just why escapes me, but it has something to do with not mistaking them for something else. How could you do that? "Ayup, I think I'll pour this molasses in my crankcase, uh hu."

[uncas]

or fry dinner in crankcase oil...
OOps. that would do wonders for one's digestive system. Don't even want to think about that.

[Stiletto]

EP stands for extreme pressure which happens at the interface between gear teeth. To my nose these oils have a strong pine like smell.

SAE 80 is a viscosity rating slightly below (EP) 90

In practical terms I think new 90grade will be better than your old 80 grade if you cant find an 80grade replacement.

[ishmael]

Pine! Let me assure you, the scent talked about by Yanks ain't pine. It's foul smelling, not like ****e or skunk, but kinda close.

Hm. I imagine different manufacturers on different sides of the globe got to pick their own scents? LOL. I'd prefer pine.

But why? I remember reading a rationale that had to do with making sure they were kept separate. There has to be some history; some damn thing to do with war, I'll bet. Keep the goobers from putting gear oil in the crankcase and the custom stuck.

I don't know about the antipodes and pine, but I remember it as quite a conscious decision to put garlic(or whatever it is) in the gear oils hereabouts. If no one comes up with an answer I'll ask Kevin, my across the road mechanic. He'll probably look at me, blankly.

[Gary E]

I remember it as quite a conscious decision to put garlic(or whatever it is) in the gear oils hereabouts. If no one comes up with an answer I'll ask Kevin, my across the road mechanic. He'll probably look at me, blankly.

Garlic?? Pine??? you been the woods waaaay to long...Do you plan on keeping your nose close to it? or using it as after shave???
He will join others with that look.

Now that you have decided to change the oil, which by the way is ok if you do, and ok if you dont, but should be changed if it has water in it, no water? it's fine for many many years.

Now that you are fully convinced that it is to be changed let me ask you if you EVER changed the oil in your car's automatic transmission? ... how about the manual transmission?.. how about the differential gear oil? You EVER change any of those?

Those oils are made to last pretty much FOREVER unless you contaminate them with water or ground up metal such as bad bearings or broken gears. There are hydraulic machine tools that are running today with the same oil as originally installed in the 60's, but they have filters that remove everything above 5 microns. For these machines, new oil from the barrel is aprox 50 micron, and it gets filtered with a 5 or a 10 micron filter as it is pumped into the machines tank.

[ishmael]

Gary,

They have been infused with something to set them apart. That smell of gear oil is because of an additive. I'll bet you five bucks, or five hundred. Oil, no matter what way refined, has a pretty bland smell.

I'll go to the auto parts and buy a quart of 80 weight if they've got it, something close if they don't, in one of those squeeze tubes, and squirt it in there. It's only like a pint in the lower unit, so I imagine one good squeeze till it tops and then quick fit the top plug.

No problemo, as we say today in honor of "Illegal Imigrant Day."

[Stiletto]

When I said pine I meant pine tar type smell, it still aint cologne.

Let us know how much it actually takes.

[ishmael]

I can give you the volume right now. 195 cc. Approx. 3/8 US or IMP pints. Tiny. From the manual.

That US and Imperial pints are the same brings up and an interesting ditty.

"A pint's a pound the world around."

LOL. Course, it ain't quite true. A pint of liquid mercury weighs quids more that a pound, eh? But, you get the idea. It comes from measurment of water. 16 oz.

[pipefitter]

Here's another thought. If it is an older motor/gearcase,sometimes,heavier gear lube was used for those that had a little slop in them.I had nearly siezed a bearing in my original tranny in the bronco. Was water in it and the transmission was binding and smoking hot. Drained it,rinsed it out with kerosene and refilled it with 90/185 and rocked the truck back and forth gaining a little at a time. Finally started it up and drove from St Louis to Tampa and for 4 more years after that.Still have that transmission but swapped it for a 4 spd.

[Stiletto]

I thought a quart would be a bit much.

So, if an imperial pint and a US pint are the same why is there a difference in their gallons.
I learnt at school: eight pints; four quarts to a gallon.



Have you replaced the Mazda yet?

[ishmael]

"So, if an imperial pint and a US pint are the same why is there a difference in their gallons."

The same question troubled my noggin. Someone trained in the imperial school? I'm guessing they aren't but the amount is so small that the Japanese who printed the manual got away with "approx."

But that doesn't explain my ditty, which may be yet another example of American hubris.

Thus the reason for our half-assed attempt to convert to metrics when I was a whippersnapper. I did all my science training and work in metrics, but try asking for a liter of milk at the corner store. LOL.

P.S. I never heard back from the seller of the Jeep, so the Mazda is still on the road. It's weeping coolant from some occult place, the fuel pump threatens every once in awhile, but she's still kicking.

[Stiletto]

Gee Ish, you're up and on the forum early today.

Google tells me that a UK quart=1.13625 litres

US quart =.94625 litres

The historical context of why there is a difference interests me but I'll leave it for another day.

I reckon you should keep your eye open for another jap vehicle.

Goodnight.

[ishmael]

Sleep tight. It's six twentyfive here. I'm usually up at five this time of year.

It's so tempting to buy a Ford. For half the money of a used Toyo Tacoma you can have a Ford Ranger. There's a reason for this. Buy the Tacoma, and like the Jap Mazda, you can count on it to go when you turn the key.

[Gary E]

Jack,
You never did answer this....

Now that you are fully convinced that it is to be changed let me ask you if you EVER changed the oil in your car's automatic transmission? ... how about the manual transmission?.. how about the differential gear oil? You EVER change any of those?

[ishmael]

Gary,

Yes. When I bought the Mazda, 90,000 miles ago, I changed out all the gear oils with synthetics. They've been changed once more since. It's a five speed manual. Why do you ask?

The lower unit on this Nissan motor has so few hours on it. It's a kicker on a sailboat. The plan is to change out the lower unit oil before I use it this year.

Answer your questions?

[P.I. Stazzer-Newt]

...

That US and Imperial pints are the same brings up and an interesting ditty.

"A pint's a pound the world around."

.... It comes from measurment of water. 16 oz.

Not here it aint.

The unit of beer is the Pint thats 20 oz. and short measure is not appreciated.

Twenty oz to the pint, two pints to the quart, four quarts to the gallon.

Gallon weighs ten pounds.

[ishmael]

I kinda figured something like that. Ah, metrics. But it just wouldn't be the same giving a holler to the barkeep for another "three quarter litre of ale, all 'round."

I imagine that ditty was just a mnemonic, to teach basic liquid measure to a kid.

[Meerkat]

I think oiling your lower unit is a personal decision. :D