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I have a 2000 8hp Johnson 2 stroke outboard and the lower unit has had water intrusion 2 years in a row. No oil out, only water in. the lube is milky at seasons end. After the first leak year I did a pressure and vacuum test at both the lower and upper screws and had no loss of pressure... zero after 30 minutes. I forget the pressures I used but I had looked them up and didn't do this randomly. If anyone knows the proper pressure I'll do it again. I had an old Evinrude with the the same problem. I have to suspect the Nylon washers which to me have never made sense. The screws do not have a groove for a rubber O-ring so I don't think this is the issue. The Nylon still makes no sense to me and it has got to be the slow leak point. Oil too viscous to leak out but water eventually gets in. QUESTION: Any reason I can't use one of the red Yamaha washers?
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It's not likely that the nylon washers would be at fault... possible but not probable.
The test pressure should be 7 to 12 psi. When testing, apply hand pressure sideways to the propshaft and driveshaft. It's been my experience that a slight wear in a bearing or bushing at either of these to areas would result in leakage BUT only when the engine is running at a certain rpm which the hand pressure sideways brought to light. -
Thanks Joe. Good info which I have not seen before and did not do. I'll get right on it. And thanks for the pressures.
If I do have a leak there, is the job DIY or do I need the shop?Comment
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I retired back in 1991 my friend so I have no knowledge of that engine's design or circuitry, however the smaller hp models have never offered much difficulty pertaining to replacing those seals.Originally posted by drchpete View Post
Hopefully you have a service manual... if not, it would be a good investment to obtain one.
However... first things first. Let me know if that suggested procedure reveals the leakage point.Comment
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Thanks. I'll get on it sometime this week and I will let you know how it turns out.Comment
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OK Joe, I tried it at 12 psi and nothing. No drop whatsoever in the pressure. I pushed and pulled and put sideways pressure on the prop shaft and nothing. Pulled the prop before doing too. All looks good in there but I assume I cant see the seal anyway. I applied the pressure from the top screw and the bottom screw and still nothing. Nothing past the screws / washers either obviously.
Perhaps this is the problem anyway when in gear under load? Should I just change out the seals anyway? What else could it be?Comment
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That result is strange... something should have shown up.
And yes, a lot of gearcase leakage will take place only when underway... the reason for the pulling, shoving, the shafts sideways etc.
I'm not familiar with the shift shaft setup on that model... possibly the "O" Ring seal is failing? Did you try moving that around also?
And to answer your question.... yes, if water is entering that gearcase and the location of the leak can't be found... if it were me, I'd replace all the seals for peace of mind if nothing else.Comment
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I think I'll just use it for the season and see if it happens again. Then change the seals no matter what. Thanks so much for your input.Comment
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