15 HP Evinrude gear oil leak

goblerblaster

Petty Officer 2nd Class
Joined
Dec 26, 2011
Messages
176
My 15 HP 1982 Evinrude seems to have an intermitant lower unit gear oil leak.

I put new gear oil in it a couple of weeks ago, ran it several times, and never saw any gear oil leaking or on the ground. Then a couple of days ago, I ran it on muffs in my yard for a few minutes and the next day noticed a slight gear oil leak. I pulled the prop- looking for fishing line in the prop seal and found none. Actually, the gear oil was not leaking from the prop shaft seal that I can see, but was pooled behind the thrust washer under the carrier bearing housing.

I hosed and cleaned out all of the leaking oil, ran the motor for 30 minutes on muffs, went from forward to neutral to reverse several times,let all the water drain, crammed a white paper towel under the carrier bearing housing checking for oil and found none, put a dry piece of newspaper under the lower unit, and then waited till the next day. The next day there was no oil on the newspaper or any that I could wipe out of the lower unit. I thought the problem was resolved. So, I ran the motor on muffs again for about 5 minutes yesterday morning. This morning I went out and there was oil on the outside of the prop- none on the inside of the prop, and a half dollar size drip of oil under the prop on the ground. I pulled the prop and could not see any oil coming from the prop shaft seal, but water/oil mix under the carrier bearing housing. When I take out the screww where you fill the lower unit with gear oil, the oil comes out pure and clean with no apparent water in it.

Any ideas on where this would be leaking ?? Also, if I have to pull the carrier bearing housing to replace the bib "O" ring on the back of it , or the prop shaft seals, is there any good way to prevent the two bearings and spring on the shaft from coming out when I pull the housing?
 

goblerblaster

Petty Officer 2nd Class
Joined
Dec 26, 2011
Messages
176
I didn't smell it, but I am pretty sure that is what it is. Seems too thick to be gas.. What is your suspicion ??
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,607
but...smell it. Running on muffs doesn't clear the exhaust and unburned fuel like running in the lake.
 

jakedaawg

Rear Admiral
Joined
Jun 26, 2012
Messages
4,275
I dont know what other shops charge but if you came to my shop i would pressure test ut for you. Drain the oil take it to a shop and ask them to pressure test while you wait. It doesnt take a.mechanic. any yard guy/girl can do it. If it fails it is fairly simple to just replace all the seals. You dont even need to know which one is bad. Bring a bag of cookies or something with you. There is always a tech with a sweet tooth and a lunch break.
 

goblerblaster

Petty Officer 2nd Class
Joined
Dec 26, 2011
Messages
176
It definatley smells like lower unit oil.. I don.t think the marine shops around here work for cookies, but it is for sure leaking gear oil.
 
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