Water in lower unit oil

Have a question about your motor? All motor talk and questions go here.
Post Reply
ktoelke54
Posts: 64
Joined: 05 Sep 2016, 05:50

Water in lower unit oil

Post by ktoelke54 » 29 Sep 2016, 16:42

Recently purchased a 1985 15hp Johnson. I checked the gear lube when I bought the motor. I have ran the motor a few times now, pulled the lower unit plug and oil is milky. I replaced with fresh lube. What should be my next step? The screws were tight and the little gaskets were on them when I drained the oil.


Sent from my iPad using Tapatalk

RazorBaits
ktoelke54
Posts: 64
Joined: 05 Sep 2016, 05:50

Re: Water in lower unit oil

Post by ktoelke54 » 29 Sep 2016, 16:42

Oh, the oil looked new when I bought it.


Sent from my iPad using Tapatalk

User avatar
Pappy
Donor
Posts: 2736
Joined: 15 May 2010, 00:38
Location: Central Florida

Water in lower unit oil

Post by Pappy » 29 Sep 2016, 17:51

Your next step is to find where the water is entering the gearcase. If you are lucky it will be a driveshaft seal.

User avatar
Johnny
Donor
Posts: 3194
Joined: 02 Mar 2014, 19:52
Location: Central FLORIDA - The Sunshine State -

Water in lower unit oil

Post by Johnny » 30 Sep 2016, 16:33

The reason the oil looked new when you bought it is the previous owner
"probably" changed the oil and never ran it in water after that.
= hence no water in the oil when you bought it.

with many thanks to Pappy, I was able to overcome
my intimidations of breaking open the gear case . . .
To replace the prop shaft seal is pretty straight forward.
To dig down and replace the shift linkage seal is a bit more complicated.

Order the complete Gear Case Seal kit from e-bay or Marine Engine
http://www.marineengine.com/parts/johns ... n=Gearcase
and using your parts book, take it all apart, taking photos as you go.
clean as you go - take notes as you go.
don't muck up the head on the pivot pin or loose the detent spring or the two little balls.
work on a clean table (the kitchen table is perfect for this).
the good old YouTube has several good videos on how to pressure test to check for leaks
and to replace the seals with a seal kit.

oh, it is also highly recommended to replace the impeller while you have it open.





.
http://www.tinboats.net/how-to-build-a-transom/
http://www.tinboats.net/varnish-vs-polyurethane/
All about Primers = http://www.tinboats.net/primer-and-paint-basics/
Paint, Thinners and Applications = http://www.paintingforpainters.com/

1959 Crestliner Commodore 14'
1959 Lone Star Malibu 14'
1958 Johnson 35 RDE-19 Sea Horse
1958 Johnson 35 RDS-20 Super Sea Horse

Kier
Posts: 123
Joined: 13 Jan 2014, 01:04

Water in lower unit oil

Post by Kier » 30 Sep 2016, 21:53

On the mercury's the water pump kits have seals coming from shaft side that are easily replaceable. Another cheap insurance is to replace the o-rings on the fill screws. Hopefully it is not coming from the prop side. There are some Youtube videos on how to replace those seals but they seem complicated. The other option is to change it more often till it dies. I recently purchased a 50hp mercury classic on a bass tracker and took it out the first time and the lower unit grinded to death due to only water in the lower unit. It cost me 350 to buy a used one on ebay that was pressure tested.

ktoelke54
Posts: 64
Joined: 05 Sep 2016, 05:50

Re: Water in lower unit oil

Post by ktoelke54 » 30 Sep 2016, 23:45

Thanks Johnny, Pappy, I'll give it a go.


Sent from my iPad using Tapatalk

Post Reply