Lower Gear Case Leakdown 1958 Evinrude 10 hp

[Mike Nazarenko]

Just finished replacing the following for my 1958 Evinrude 10 hp Sportwin:

1. All parts from Sierra 18-2682 lower unit seal kit.
2. New lower drive shaft bearing carrier with new oil seals upper and lower, new bearing housing gasket.
3. New prop shaft oil seal and new o-ring
4. New pinion gear .
5. New forward gear.
6. New spaghetti seal for lower housing.
7. New water pump housing, impeller, wear plate.
8. New shift rod rod o-ring.

Assembled all parts with Permatex Ultrablack gasket maker on all metal to metal surfaces: bearing housing gasket to drive shaft bearing carrier assembly, water pump housing to the wear plate to the drive shaft bearing carrier.

Have not put any lower gear oil into the unit.

Pressure testing the unit – – 7 psi down to 6 psi in about a 1/2 hour. Could not detect any leaks with soapy water solution at any of the key areas.

In videos I have watched, Old JohnnyRude rebuilding lower gear case, pressure is supposed to hold 6 psi overnight.

Suggestions: Is this level of leak down acceptable. I’ve checked all the visible housings multiple times with soapy water.

[Mumbles]

It would be impossible to perfectly seal any shafts with signs of wear on them, especially in a 63 year old motor, so I would say you are good to go. Just check the oil occasionally for water as is normally done.

1 user thanked author for this post.

Mike Nazarenko

[frankr]

Submerge it under water and look for bubbles

1 user thanked author for this post.

Mike Nazarenko

[fleetwin]

Like Frank says, submerge the whole gearcase in water/no soap for the pressure test. To answer your question, thinking it will hold pressure overnight is a bit optimistic, but should hold for a half hour. Please don’t forget that the pressure tester/hose connection may be at fault causing the leak down…
With the gearcase totally submerged in clean water/no soap, while pressurized, spin the shafts and shift the gears, look for bubbles. But, make sure the impeller housing (no impeller) is secured snuggly over the upper bushing/seal housing before doing the test, other wise the pressure will just pop the upper bushing/seal off its gasket.
Grooves in the shaft seal areas make it hard to seal these areas, even with new seals…Grooved shafts should be replaced, although some guys have had luck pressing the seals farther into their housings so the seals no longer ride on the grooved area….
This small gearcase used on the 10hp won’t tolerate much, if any, water intrusion, so the sealing job has to be as close to perfect as possible. The best test of your sealing job will be to drain/inspect/refill the gearcase after using the engine a few times…Signs of water indicates something isn’t sealing well enough…

[crosbyman]

and in a worst case scenario….. some folks just change the oil mid season or twice and refill will a new load of oil. use a good quality gearcase oil which will emulsify some..water between refills

Joining AOMCI has priviledges 🙂

[itranwheniparkedit]

i’ve had luck running john deere cornhead grease in units with seal issues. Mercury marine recommened 105 lubriplate on lowers from that time frame. They didn’t seal or build lower units back then like they do now plus you have a lot of wear against you. Don’t get to much water in your oil!

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