Lower oil leak - 55 hp

[Jeffe74]

I noticed a bit of oil leaking from the join in the lower maybe the second time we had the boat out. Changed the oil and had the boat out another few times and drained it the other day.

I'm guessing water is getting in as well.

​​​​​​I bought the 18-2636 seal kit. I'm going to pull the lower off and bring it in for the winter, then I can get to it when I get to it.

I did pressure test it in the spring and didn't notice any leak there, but maybe I should have used some soapy water on the seam.

​​​​​​Any tips and tricks are appreciated

Thanks,
Jeff

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[jerryjerry05]

Do the test before the rebuild.
That way you'll know where to pay special attention.
Some times the seal under the water pump can cut a groove in the drive shaft.
If that happens? a new seal might not help.
Adding a shim under the seal can the seal up on the shaft and stop the leak.

 

[The Force power]

Seeing oil leaking at the joint of the mid-section & the LU would indicate to me, that oil is coming out the top-seal under the water-pump housing. (Perhaps there was too much oil in OR water got in and pushing the oil to the top)
When pressure test the LU ( approx. 7 psi) have a pressure-gauge on it to see if the pressure drops & soapy solution spayed on is also a good method.
Turn the shafts & move the shift-shaft while pressurized; to see if the seals hold in all positions/moving parts.

 

[Tech Tony]

Its possible it could be 2 stroke oil from the exhaust also.

 

[The Force power]

Its possible it could be 2 stroke oil from the exhaust also.

Possible, but the pictures don't show evidence of that

 

[Jeffe74]

It's definitely gear oil. I haven't taken it off yet, the weather turned. Later this week it's supposed to be above freezing again

 

[jerryjerry05]

Make sure the drain plug seals get changed.
Don't remove the screw on the side unless it's leaking there.
In 35 years I've never seen one leak there.
The plastic crush type are usually a 1 time use.
You can use Mercury seals, they can be used more than once.

 

[Jeffe74]

I got the seals changed out yesterday, except for the aerofoil (hydrofoil?) shaped seal between the upper and lower, I ended up using anaerobic sealant for that..my kit didn't come with that seal.

Laings outboards has pictures of the kits, which I went by, but my engine doesn't have the groove for the large o-ring. Laings shows the aerofoil seal only from 1959-66.. ?

Hopefully the sealant will be okay, the fit between the parts seemed really good. I'll give it another day, then I'll pressure test it

 

[Jeffe74]

A couple pics

 

[jerryjerry05]

Seal kits, they make one kit with(supposedly) all the seals needed to fix a LOT of motors.
That kit can fit 50-100 different lowers???

O-rings make sure the groove is very clean and the o-ring is greased on top of the o-ring and nothing under the o-ring.
Same with sealer no sealer under the o-ring just on top.
The grease/ sealer lifts the o-ring up and can stop the parts from going together.

 

[Jeffe74]

Thanks Jerry

Laings shows a 1074A kit with the seal I needed.
Their 1074 kit just shows the o-ring. I do have a couple of small o-rings left over , maybe for a different model

I'll see how the pressure test goes, but I think (hope) it's going to be fine.

 

[Jeffe74]

No problems found with the pressure test.
I used permatex anaerobic sealant between the two sections for future reference..