Lower unit plugs

volnavy001

Cadet
Joined
May 17, 2019
Messages
10
I just changed the lower unit oil on my 1990 Johnson 15hp outboard and noticed that there was not gaskets or o rings on the screws. Is this ok? There was not any water in the lower unit.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,501
No there should be a seal on the screws.-----Some screws have an o-ring in a groove.-----Double check and see if the nylon washer stayed in the housing.----Caution.----Make sure you have the screws sealed as the price of new gears / bearings will shock you.
 

volnavy001

Cadet
Joined
May 17, 2019
Messages
10
I double checked and the gaskets/ o-rings were definitely not there. I bought original omc replacement gaskets (the same ones listed in the manual) but when I installed them the screws would not seat flush with the lower unit housing which worried me. What am I missing?
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,471
I think the drain plugs that year should have o-ring seals in the plugs themselves. If not, use what you have now. Won’t be exactly flush, but will seal your gearcase normally.
 

thatone123

Banned
Joined
Mar 7, 2009
Messages
707
I've come across this also in the same outboard and there did not seem to be any seal unless I missed it.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
The drain plugs that require O-rings have gruves in them for the o-ring. Don't use the 311598 flat washer on them.
 

volnavy001

Cadet
Joined
May 17, 2019
Messages
10
OK. I talked to a local guy who said they probably seal themselves. Thanks for all the help.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,501
???----" Seal themselves "----That sounds good.-------Hopefully you have checked the price of gears and bearings should water get in there.------There have to be seals on those plugs !!!
 
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