1957 fd-11 johnson lower keeps leaking

[stwaller]

I have a 1957 fd-11 18hp Johnson that my son and I are working on. We rebuilt the lower and everytime we put the skeg back on and fill it with oil it leaks out of one of the middle screws. I've drained the oil and took the skeg off and resealed it with more seal compound and get the same result. Anyone know why this keeps happening?​

 

[racerone]

Any close-up pictures of the condition of the surfaces around that screw.-----4 pictures.----Any cracks.

 

[Crosbyman]

I usually seal the screw heads with sealant. check matingsurfaces for flatness and use proper spaghetti seal size. on my last reseal I could only find spaghetti a bit thicker (.103 I think it was) but it worked out OK .

try wrapping screw threads with a couple of layers of yellow teflon tape

do a GC pressure test before refilling with oil to confirm proper sealing...spray soapy water on the gc exterior.

https://www.bing.com/ck/a?!&&p=df6f871e3886fcabJmltdHM9MTY5NzUwMDgwMCZpZ3VpZD0xNWNlY2Y1MS1lMTllLTZlOGUtMjEyOS1kYzYyZTBhNTZmOTImaW5zaWQ9NTE4NQ&ptn=3&hsh=3&fclid=15cecf51-e19e-6e8e-2129-dc62e0a56f92&u=a1L3ZpZGVvcy9zZWFyY2g_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&ntb=1

 

[stwaller]

Any close-up pictures of the condition of the surfaces around that screw.-----4 pictures.----Any cracks.

 

[stwaller]

It's leaking feom the center screw hole.

 

[racerone]

Obviously it had water in it and froze.----Any pictures of the inside.-----I would say that housing is warped to a degree from welding.-----Or mating surfaces are damaged , resulting in the leak.----Easy fix for me here.

 

[silverbul]

A flat file and a little work. jmo

 

[stwaller]

Obviously it had water in it and froze.----Any pictures of the inside.-----I would say that housing is warped to a degree from welding.-----Or mating surfaces are damaged , resulting in the leak.----Easy fix for me here.

What is your easy fix?

 

[racerone]

Pressure test and see exactly where the leak is.---Then repair that leak with say ----" lumiweld" ---brazing rod.----Better yet is to replace that housing.

 

[Crosbyman]

if only one screw is leaking ....try easy stuff first... teflon tape on the threads and some sealant under the screw head Let the sealnt dry then pressure test
at 10psi with soappy water

jmho

 

[stwaller]

if only one screw is leaking ....try easy stuff first... teflon tape on the threads and some sealant under the screw head Let the sealnt dry then pressure test
at 10psi with soappy water

jmho

I will, thanks for all the help!

 

[silverbul]

I will, thanks for all the help!

Stupid question, why would you pressure test the lower unit when there usually is no pressure in the lower unit? just grease or 90 weight. blow out seals that are not leaking. jmo

 

[silverbul]

if only one screw is leaking ....try easy stuff first... teflon tape on the threads and some sealant under the screw head Let the sealnt dry then pressure test
at 10psi with soappy water

jmho

Doesn't the gasket go around all the screws? i believe this is a mating issue. jmo

 

[Crosbyman]

Stupid question, why would you pressure test the lower unit when there usually is no pressure in the lower unit? just grease or 90 weight. blow out seals that are not leaking. jmo

never done a pressure test have you ??

GC leaks at shift shafts. drive shafts prop shaft seals and anywhere on the mating service of the spaghetti seal

fyi

https://www.bing.com/ck/a?!&&p=eab14058f99cc8a8JmltdHM9MTY5NzU4NzIwMCZpZ3VpZD0xNWNlY2Y1MS1lMTllLTZlOGUtMjEyOS1kYzYyZTBhNTZmOTImaW5zaWQ9NTE4NA&ptn=3&hsh=3&fclid=15cecf51-e19e-6e8e-2129-dc62e0a56f92&u=a1L3ZpZGVvcy9zZWFyY2g_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&ntb=1

 

[racerone]

But , but a lower unit does have pressure when motor is running.-----And they do develop pressure if out in the hot sun !!

 

[silverbul]

never done a pressure test have you ??

GC leaks at shift shafts. drive shafts prop shaft seals and anywhere on the mating service of the spaghetti seal

fyi

https://www.bing.com/ck/a?!&&p=eab14058f99cc8a8JmltdHM9MTY5NzU4NzIwMCZpZ3VpZD0xNWNlY2Y1MS1lMTllLTZlOGUtMjEyOS1kYzYyZTBhNTZmOTImaW5zaWQ9NTE4NA&ptn=3&hsh=3&fclid=15cecf51-e19e-6e8e-2129-dc62e0a56f92&u=a1L3ZpZGVvcy9zZWFyY2g_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&ntb=1

Never had too. i always did it right.

 

[silverbul]

But , but a lower unit does have pressure when motor is running.-----And they do develop pressure if out in the hot sun !!

OKAY.

 

[silverbul]

Lower units on a outboard are just like a differential on a car, truck. They do NOT build up pressure, only leak through gaskets, seals. Prove me wrong.

 

[tphoyt]

Diffs have vents do they not?
Any good mechanic would pressure test a LU for diagnostic purposes and to confirm a thorough reseal job. Jmo

 

[silverbul]

Diffs have vents do they not?
Any good mechanic would pressure test a LU for diagnostic purposes and to confirm a thorough reseal job. Jmo

I guess we will agree to disagree.