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  Water in lower unit - a death sentence?

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Author Topic:   Water in lower unit - a death sentence?
fly_fool posted 11-06-2006 12:08 PM ET (US)   Profile for fly_fool   Send Email to fly_fool  
When I winterized this weekend, I found that milky stuff in my lower unit. (First time I checked it since last fall) What I don't know is how much damage I have. The motor ran great all season, and there was plenty of viscosity in the oil, but I don't know the extent of any damage to the gears.

I know my limits. I already have an apointment next month to have the LU removed and WP impeller replaced, and notified the shop of this problem. Hopefully new seals will be enough to solve the water problem. The motor ran great all season, and there seemed to be plenty of viscosity in the oil. Is this a valid reason for hoping for a minor repair?

Since this motor ('88 Yamaha 90HP) is pretty old, should I have them do a compression test before they start on the LU? I don't want to have to buy a new motor, but I also don't want to throw money at one on its way out.

Anxious in Maine.

Don88outrage posted 11-06-2006 01:27 PM ET (US)     Profile for Don88outrage  Send Email to Don88outrage     
Lower unit oil is water soluable, what you're seeing sounds normal for end of the season, especially for an older motor. Change it prior to putting it up for the winter, any water mixed with the oil could freeze and create a real problem. You should be all set for that great striped bass fly fishing in your neck of the woods next spring.

Tight lines

tpnaquin posted 11-06-2006 01:39 PM ET (US)     Profile for tpnaquin  Send Email to tpnaquin     
I just recently asked the same question at my dealer. I was told that as long as you caught it soon enuff, you would be fine. The problem comes in if your lower unit gears rust. (Naturally, the dealer suggested to bring it in asap)
Kevchap posted 11-06-2006 04:13 PM ET (US)     Profile for Kevchap  Send Email to Kevchap     
You will be able to tell next year if you have a rust problem, the gearlube will be very black in color.Gearlube gets black if there is rust in the lower unit or gears. I wouldn't spend money on a major LU rebuild unless you have problems in the future. Just my opinion.
contender posted 11-06-2006 04:26 PM ET (US)     Profile for contender  Send Email to contender     
You have to change that oil and find out were it is leaking, If the problem is not address the water will ruin the lower unit gears, (drain the oil/water mix and put fresh oil back in). The lower unit needs to come off the engine, the water pump seals and area need to be checked so have your pump changed/replaced. The other area were it could be leaking is the seal for the gear case (lower unit) behind the prop. You will need a special tool to pull out the gears (gears puller) with extra long bolts, the problem here is the gasket, sometimes something gets behind the seal itself and expands thus letting the water in. (this happens more in salt water a grain of salt will expand in time and push the gasket out). another possible problem is you could have a crack in the case,(hit anything lately) hope not this one. I have even seen fishing line hurt this area before. You stated you do not have the savy to do this, this is one time the dealer is correct, you need to get it in and fixed, don't forget to drain the oil and replace it...good luck.
Buckda posted 11-06-2006 06:53 PM ET (US)     Profile for Buckda  Send Email to Buckda     
Certainly not a death sentence, but the source of the water needs to be found and then addressed so that no more water intrudes into your gearcase.

It could be a flook/freak incident.

I think the most common cause of this is failure to remove the old fabric washer/grommet on the drain plug before putting the new washer/grommet on when changing lower unit lube.

Two washers are NOT better than one and may allow a small amount of water to intrude into the gearcase over the course of a season, causing milky gear lube.

If you live in a climate where freezing occurrs in the off season, this water in the gearcase can freeze and cause a crack in the lower unit casing - not a good thing.

As others have mentioned, it can also cause your gears to rust - also not a good thing....this is why you should change your gear lube in the fall, after your final use of the boat - waiting until spring without inspecting the lube for water may mean significant lower unit damage - over what? A 30 minute job. Not worth the risk, in my opinion.


kingfish posted 11-06-2006 07:01 PM ET (US)     Profile for kingfish  Send Email to kingfish     

The correct spelling of the word you used that was intended to be synonymous with "freak incident", is "fluke".

John Flook

where2 posted 11-06-2006 10:03 PM ET (US)     Profile for where2  Send Email to where2     
Hasn't been a death sentence to the 9.5Hp Evinrude I have in the garage... If you don't find large metal flakes on the magnet attached to the lower drain bolt, you're probably safe. The shop will have the tools to do a pressure test and locate the defective seal. (I've cobbled stuff together to do this at home, but go with the pro). Definitely do NOT let the lower unit contaminated with water get cold enough to FREEZE before it goes to the shop next month. Drain the oil and refill it with straight cheap motor oil if you have to (just don't run it with motor oil in it), and get it into the shop. You will be in much worse shape if the water freezes inside the case in the interim...

I'd drain the chocolate milk colored fluid out and refill with motor oil if I knew for a fact that it was going to the shop next month and not going to be used in the interim. A shop ought to put fresh fluid back in at $9 per quart... Definitely replace the water pump while you have the lower unit off...

Buckda posted 11-06-2006 10:07 PM ET (US)     Profile for Buckda  Send Email to Buckda     
Geez John.

Sorry. I can understand how you might be sensitive to the spelling in this particular case!


kingfish posted 11-06-2006 10:53 PM ET (US)     Profile for kingfish  Send Email to kingfish     

Not sensitive at all - just trying to be helpful; at least you got the pronunciation right...


fly_fool posted 11-07-2006 09:32 AM ET (US)     Profile for fly_fool  Send Email to fly_fool     
Thanks all. I have replaced the LU oil, and will get the whole thing checked out next month, when the shop gets over the fall rush. (I may have to shovel some snow to get my Montauk out of the shed!) I think/hope my problem may have been a bad washer at the fill hole, but we'll find out in a month. It sounds like once the LU comes off, it's relatively easy to replace the seals.

Sleeping better in Maine

RMS posted 11-07-2006 12:43 PM ET (US)     Profile for RMS  Send Email to RMS     
Last fall. when winterizing my 1989 Yamaha 90hp I realized there was water contamination of the lower unit. Looking at the prop seal, I could see the milky fluid present, so I surmised that the prop seal was bad. I removed the lower unit from the outboard and brought it to the local mechanic who, with some difficulty, went and changed the prop seal. Next the mechanic pulled the waterpump off the lower unit to look at the upper seal. This is when the mechanic saw the cracked housing, under the waterpump. The crack was not repairable, and I already had a fair amount of repair costs incurred. Therefore, before I had a mechanic start replacing seals, etc., I would have them look at the "big picture" of the lower unit. Good luck.
The Judge posted 11-10-2006 01:58 PM ET (US)     Profile for The Judge  Send Email to The Judge     
Don't worry about it. I have removed pure water from lowers and they lasted years after that. Do not rush into a reseal job either, could have just been the gasket. I would change the oil and let her sit until mech can look at it. No need to move boat out of garage, that lower unit comes off in about 30 seconds. Just remove bolts and drop it down and take THAT to dealer. Have him replace pump and pressure test the unit for leaks(which he should do anyway. Before you dump too much into lower unit look at the shift rod when you remove the lower. It is the skinny rod that is inside the midsection and towards the transom. It slides over a 2" shaft coming out of your lower that is splined. These are notorious for rotting until the 90's when they went to SS(duh?). To replace you have to pull powerhead and it will be about a grand if you pay to have it done so you might want to trade her in before dumping $$, etc. Chances are this has been replaced if run in salt water, they usually lasted about 10 years.

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