Reply To: Lower Gear Case Leakdown 1958 Evinrude 10 hp

[Don]

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…