Lower unit oil

[Easyrider]

I have a 2003 150 2 stroke. Is there any special problems changing the lower unit oil?

2003 206
Yamaha 150

[Juan]

just don't drop or lose the plugs and check and replace the gasket on the plug if it needs it and remove any metal shavings from the magnetic drain plug before you reinstall it.

[Easyrider]

Thanks this is my first Yammy and you never know what quirky things you could run into

2003 206
Yamaha 150

[985crabs]

Easyrider,

I have the same motor and I need to change my lower unit oil. Did you do yours yet? Any unforeseen difficulties?

[985crabs]

So I changed my lower unit oil yesterday. I'm glad I did. It was very dark and stunk like something nasty. Let's say it was the color of coffee. As it was pouring into my drain pan, I did notice a tiny streak of a milky swirl. It was as if someone put a drop or 2 of cream in my otherwise black coffee. I'm sure this indicates water intrusion, but is that very tiny amount something to be concerned about? Are my seals shot or is this normal?

[Juan]

You really shouldn't have any water at all in the oil but I don't think I'd worry about a drop or two. As long as all the oil didn't look milky.
When is the last time you changed the seal on the fill screws? That seal tends to get hard and brittle and will sometimes leak. It's a good idea to replace it every couple of oil changes..
If you haven't checked your prop, you might want to pull it off and check for fishing line behind it since fishing line can cause the seal to leak.
btw: lower unit oil ALWAYS stinks.

[985crabs]

I replaced the little gasket/washer things on the magnetic drain plug and the oil vent plug if that's what you mean. Prior to that I couldn't say. I bought the motor used 2 years ago from the Yamaha dealer after my Optimax threw a rod. I've put roughly 60 hours on it since then and, as the Fall fishing season is beginning, I thought I'd do a little preventative maintenance. I'll pull the prop and look for fouled line. Thanks.

[Juan]

Yep, that's what I meant..

[IguanaBait]

I drained the lower unit gear oil and this is what I got. I know this isn't what it's suppose to look like. What could cause this?

[IguanaBait]

Well I replaced the old gear oil with new but like you said the bottom screw had a lot of metal shavings on it, is this bad?

[Simple Man]

It depends on your definition of a lot. Some is normal, a lot is not. On a positive note, these type problems are fairly quick and easy to diagnose with continued boat use!

[Simple Man]

Jul 19, 2014 6:57:09 GMT -6 @poerover said:

..... For the record I am not a mechanic.....

But he did play one on TV....

[IguanaBait]

I wish I took a picture of the magnetic screw but I looked up some videos and they said that if there is water that it might be the prop seal so I think that will be my next to do on the list of things to check.

[Simple Man]

Jul 18, 2014 10:55:17 GMT -6 @poerover said:

Water intrusion.  That is white milky stuff Juan was talking about.  See above and check seals and pull the prop and check that seal. Those are most obvious.  If seals are okay it could be that plug might not have been seated properly and let water in.  Unless you are seeing a whole lot of metal shavings your probably okay.  That marine oil is pretty thick and tough stuff and can take some water intrusion before protection breaks down.  Just make sure and let all that old gear oil drain out as much as you can and maybe if you have enough of the recommended replacement hypoid oil flush some of it thru system before refilling. After refilling look for leaks and any oozing oil. If you don't notice any then take her out.  After a trip or few short trips recheck the oil and see if you have any more discoloration.  The milky oil with water should hopefully settle to bottom drain plug.  At that point you will know if you have a leaking seal letting water in somewhere.    

icon_goodpost

Too bad it wasn't read....

[yolo]

I think im late to the game on this one. But if your getting a good amount of water in there then its gonna be the oil seal under the water pump, i think your calling it the prop seal.

Definaly normal to have a little water in there, there are three submurdged points water can get in AND (a big and) one of them is a seal, not a water tight gasget.

Assuming all motors are consistent with the Yamaha F and Verado. The way i test if my seals are solid, drop the torpedo in water, let it sit, take it out and fill the oil from the port by prop. The water will always sit at the top since it is lighter and if water comes out then you have a problem, if not HAPPY BOATING!!!

[Juan]

Aug 5, 2014 15:29:19 GMT -6 yolo said:

The water will always sit at the top since it is lighter and if water comes out then you have a problem, if not HAPPY BOATING!!!

You sure you got that right? Oil is actually lighter (less dense) than water so the oil will float on top of the water and would come out of the upper plug before any water when filling from the lower plug. There shouldn't be any sign of water or milky looking oil unless there's a leaking seal or some other problem.

[yolo]

You are 100% correct i wrote that backwards, great catch and thank you! long day yesterday after an hour of sleep the night before working on my boat tirelessly.

After I replaced the oil seal this spring I opened the top screw and applied a little suction to the hand pump (very little to create a small vaccume) then opened the bottom to see if water came out first.

Thanks again for catching that Juan!

[Simple Man]

Any water gets in that lower unit is gonna be an emulsion (ie milky) after first trip. Them gears be spinning around....

[yolo]

I am in the water for the season so i dont check it often. I change, submerge the torpedeo (i use a 55 gallon drum that has been cut) over the water pump, start it to fill up the water pump (I dont engage the gears), let it sit submurdged for some good time and then check it like i said.

[Simple Man]

I check my lower unit once a year, when I am changing the oil.