Milky oil in lower unit.. 1997 Johnson 175

[gradyrod]

I just drained the lower unit gear oil today and noted that it was practically white in color! My quesiton is should I remove the lower unit and take it in to a dealer to do a pressure test, or just go ahead and replace the top gasket myself and take a chance it's not the gasket down at the prop shaft? I know there is a way to pressurize the lower unit to see where it is leaking from. Does anyone know how an amateur could do this?? Guess I'll do the water pump too while I've got it apart. Also, amy tricks to loosening the 5 bolts holding the lower unit on? Just removing those five ( assuming I can) should allow the lower unit to drop down, right?

Thanks!

Gradyrod
1985 Fisherman 204
1997 Johnson 175 Oceanrunner

 

[CatTwentyTwo]

Actually there are six screws, you will need to remove the trim tab to get to the sixth one. Just be sure to mark the location of the tab so that you can put it back in the same position. You will also need to put the motor in forward gear and disconnect the shift rod at the power head. The manual says to use a gage and hose connected to the oil fill hole and check to see if the gearbox will hold 16 pounds of pressure and then 15 inches of vacuum. Did the plastic washers on the drain and fill plugs look good? They can get damaged and leak also. If I were in your shoes though, I think I would let the dealer have a look at it. It probably wouldn't be more than an hours labor and if they find bad seals they will be able to take care of them for you.

 

[seasick]

If the washers were the fiber type, they should be changed every time you service the LU oil.
You should at a minimum, remove the prop to look for line wrapped around the shaft. That can kill your seals. If you find line and have water you can be pretty sure the shaft seals are shot.

There are other spots that can let water into the LU. My suggestion is too have a mechanic check the LU for leakage.

 

[no problem]

I'm not familiar with your exact lower unit. Basically assuming the case isn't damaged there is a seal under the water pump, a seal where the shift shaft enters the top of the case, and the prop shaft seal behind the prop. Oh and the washers behind the drain and vent plugs. You should be able to replace these if you are handy.
http://www.boats.net/parts/search/BRP/J ... parts.html

I'm thinking part #'s
45
23
7
27
[2] 41
[2] 42
and 89 which is the complete water pump kit.

If it were me I would dismantle the lower unit to inspect for obvious problems before purchasing the parts. good luck and let us know how it works out.

 

[gradyrod]

Thanks all! Great help from the board as usual. I did notice a tiny bit of white in the gear oil the previous season, but chose to ignore it. I did the lower unit oil change myself and used new plastic washers on both the drain and fill plugs.

Sounds like I need to take it in to a mechanic to do a pressure test to determine exactly where the leak is from. Now, do I bring him the enitre motor (boat is on a trailer) or just the lower unit (that would be easier to do at this point). From one post I see that there are 5 bolts to drop, but also something to loosen at the powerhead. How difficult is that power head step?

Thanks.

Gradyrod

 

[CatTwentyTwo]

The LU is not all that hard to remove if you don't run into problems with corrosion but like I said, there are 6 bolts, not 5. The shift rod is pretty easy, start by shifting the motor to forward and remove the air box from the front of the motor. Look down low below the bottom carburetors and to the left of center is a clevis pin that needs to be removed. Just to the right of center is a brass looking piece, use a large flat blade screwdriver to slide it to the right about 1/4 to 3/8ths of an inch. Now if you look close, you can see that the pin is clear of the shift rod and the lower unit can be dropped down.
I made up some guide pins that have been helpful when reinstalling the LU by cutting the heads off of 2 3/8 x 4 inch bolts and one 7/16 x4 inch bolt. If I remember right, the lower unit weighs about 40 pounds and they help to get things lined up when you're lifting it back into place. Good luck and let us know it goes.

PS. When you're replacing the water pump you will probably notice some play in the drive shaft. Don't panic, it's normal.

 

[BobP]

Rod, time to take it in, the prop shaft seal, drive shaft seal, and gear shift rod seal need to be done if original.

The lower unit will cost about 2500 or more to rebuild, and no seal lasts forever.

You can bring in just lower unit, remove prop.
The shift rod rod on your unit may have to be disconnect under front of motor just above cowling, it's one screw.
Even if the main seal is not leaking, I'd have them all done at that age.

You want lubicant in there, water isn't a lubricant.
And they can do the pump too, maybe a zinc or two in there.

Don't know where you are on LI, I can recommend Walter at Suffolk Marine in Babylon to do the work. If not sure about shift rod, call Suffolk Marine and ask them before doing it.

A few years ago, they were operating a mobil service vehicle to come to your door, at same charges as in shop, so that may help you too.

The lower unit is particular heavy, so need two hands to lower it. Be careful.

 

[gradyrod]

repair time to do all seals on lower unit

Went to a dealer today to see what he might charge to do all the seals on the lower unit. He said probably 2 1/2 hours plus $60 for the seals kit. Does this seem reasonable?

Also, does anyone have a recommendation for a mechanic on Long Island ? perhaps someone who works in a dealership and does some moonlighting on the side?

Thanks!

Gradyrod

 

[boatz]

I don't know about Johnson outboards. I just took the lower unit of my 1991 Yamaha 200HP 2 stroke. It was 6 bolts + one in the engine zinc. The leak turned out to be a little corrosion under the water pump. I brought the unit to my localYamaha dealer and they fixed everything including new water pump for $300.00. I did not need to put engine in gear I just did the bolts and the unit dropped out very easy.

Good Luck.

 

[CatTwentyTwo]

Re: repair time to do all seals on lower unit

Went to a dealer today to see what he might charge to do all the seals on the lower unit. He said probably 2 1/2 hours plus $60 for the seals kit. Does this seem reasonable?
Thanks!

Gradyrod

I would jump at that, it sounds very reasonable to me. There's a zink on on the prop shaft bearing housing that I'm sure they will inspect/replace while it's apart also.

 

[gradyrod]

Removed lower unit today..

ok, here's the latest. I dropped the lower unit today (thanks to all you guys for the imprtant tips on how to do it!), took it right over to a mechanic who was able to pressure test it for me right away. The lower unit wasn't holding any pressure, so he got a set of super ears (an advanced stethoscope) and id's the leak as coming from the shift rod. ok now I figure I can handle that with out too big of a deal.

First question is, since the lower unit was very milky , do I need to flush it out with diesel or kerosene ? if so how long should I let it sit until I drain it and then fill with gear oil? or, should I just refill with gear oil, run the engine in gear with ear muffs in the spring, then drain the gear oil and refill with fresh, all before launching?

I figure to replace the water pump as well while I have the lower unit off. Any other suggestions welcome!
Thanks all!

Gradyrod

 

[Maritime Matt]

When we have a gearcase leak, we always do the upper drive shaft seals that are under the water pump and the shift shaft seals. Make sure the shift shaft lenth is measured before you remove it. They have a set length they need to be. The gearcase is off, just do both. Waterpump kits are under $100, replace it. Propshaft seals are an option unless there leaking. Use OEM parts. HPF gear oil too. Its the blue colored stuff. Can also use Quicksilver Hi-Performance Gear oil also. I use it in every gearcase. No need to flush the gearcase. At the next change you still might see some white with the blue/green, don't sweat it.
I do it for a living and have done many.
Capt.Matt

 

[gradyrod]

Thanks Matt, now when I replace the gaskets do I use permatex or some other gasket cement (like RTV silicone)? Do I coat all the water pump bolts with this cement or just grease them with OMC Triple Guard grease?

Last question, what's the best way to work on the lower unit? Lie it on its side on a work bench or build some sort of holder that would keep the unit straight up?

Thanks-- I am getting ready to do this!!!

Gradyrod

 

[CatTwentyTwo]

Get a can of the BRP gasket sealing compound and use it on the gaskets and all of the water pump and lower unit bolts, the stuff works great and is what is recommended in the OEM manual. I use a set of saw horses to work on the lower unit, put them close enough together to set the cavitation plate on and then use a couple of clamps to hold them together.

 

[BobP]

GradyRod had PM'd me. I need to correct myself.

I believe it's Harold (not Walter) at Suffolk Marine as top mechanic, and they may no longer be an OMC service/sales dealer, they used to be. My memoyr is not what it used to be for sure.

They worked on my yamahawsa few years ago. Bought them there 5 yrs ago. Jimmy was owner.
Don't know what has transpired since then.