Milky Gear Oil

[muskielaw]

I am winterizing my boat myself this winter and have drained my gear case. It is a 2000 Yamaha 150 HPDI. The question I have is how to tell if the gear case oil is milky and what I need to do. Having never seen this oil before it looks blue with a little white tint to it, is this normal or is this forsure what is refered to as milky? Is any white tint bad? The new yamaha oil I have does have a blue tint but I have not dumped a bunch out to compare if there is any white. If it is milky does that mean $$$$$?

[LegattoAD]

Milky appearance means that water got into it somehow. Likely just a leaky seal, for a guy like me who's not that mechanically inclined, a quick trip to the mechanic would be the best way to tell for sure what happened.

[CAMAN]

Having a slight milkyness to it is fine, its usually from the condensation that builds up inside. When it looks like a glass of milk is when you need to be worried.

[boatfixer]

The only way to be sure is to have it vacuum tested. How long has it been since you ran it last?

[muskielaw]

just ran the boat yesterday. Runs great. Bought it used this year so don't know when the last time the gear oil was changed.

[Valv]

You can replace the oil for this winter, better do it asap. Problem with milky oil is water will freeze, expand in the case and crack it, it's a very expensive fix.

Just drain it and refill it even with cheap oil, until spring, then you will need to have it checked.

[delcecchi]

I had that once on my 9.9 merc. I had somehow left the gasket off the fill plug. Won't do that again.

[hydro]

Muskielaw,

I would not make any decisions on what you saw just yet. If you ran the boat before you checked the oil, it is normal for it to look a little "milky" for a while. The oil gets churned up in the gears and the milkyness is just some air mixed in. I suggest you let it sit for a few days and check again. If it is still milky color you may have a problem with water and it's time to get it checked out.

In any case, I suggest that you change the oil prior to the winter freezing season, just to be safe.

[TruthWalleyes]

I just bought a used motor this year, and want to check the gear oil for any water. I bought new gear oil, but cannot get the plugs out of the motor. I got a larger/wider screw driver yesterday to help, haven't tried that yet, will tonight. Any advice on getting those plugs out?? I may need to find a torch and heat up the area around the plug if i struggle today...would hate to strip that plug!

[hydro]

NO NO NO! Do not use a torch.

Get a large flat screwdriver with a square shank. Be sure the blade is square and has sharp edges. Put a small crescent wrench on the shank and you will be able to get the plugs out. If they are worn or stripped, just go to the dealer and buy some new ones. Don't forget the gaskets!

[CAMAN]

I agree with hydro, just to add to his post, try taking a large round punch and hammer and give the plug a tap. That will usually shock it enough to loosen it.

[Ralph Wiggum]

I would not make any decisions on what you saw just yet. If you ran the boat before you checked the oil, it is normal for it to look a little "milky" for a while.

I agree. I usually check mine after the boat has been sitting a few days. If there is water in it, it will sink and come out first when you pull your drain plugs.

[TruthWalleyes]

Gave it the "Tap", Worked like a charm. Thanks CAMAN.

I was less than excited to see the water poor out though!

[hydro]

Water in the gearcase is never a good thing. Time to pull the prop and look for fish line on the propshaft. That's the most likely culprit. Luckily, the fix is a new prop shaft seal which is not a complicated job.

[Valv]

As we mentioned above, drain and refill your case with new oil, before hard freeze sets in. You can use any gear oil TEMPORARILY until spring, but remember to switch when season starts.

Another choice would be to find a mechanic that can overhaul your lower unit through winter, it might be cheaper than rush it in spring time.

BTW, one of the most common causes of water in lower unit is caused by the loss of the small plastic gasket on the fill and vent screws. Be sure your motor has both, it won't hurt buying new ones, they are just pennies, but don't put 2 of them on top of each other.

It's very common to drop it when checking the lube.