Johnson Seahorse '75 25hp

[ColdPat]

I'm taking on a little water in the lower unit. I put some ear muffs(square, works great when you take off the little slow speed inlet) on it yesterday. After that, I checked again and oil looks good. Could the leak be coming from the prop seal. I read somewhere that I can take the lower unit off without dropping the lower unit. ie turn upside down and take off bolts. Is this true? Could I change prop seals like that?

 

[Joe Reeves]

Re: Johnson Seahorse '75 25hp

Drain the gearlube by removing both of the large slotted screws, then replace only one screw. It doesn't matter if you replace the drain/fill screw or the oil leverl screw. Now apply 7 to 12 pounds of air pressure to the open screw hole.

This should reveal the leakage area by sound or sight.

 

[ColdPat]

Re: Johnson Seahorse '75 25hp

Thanks for answering so quickly. How can I apply pressure to the lower unit? I read that a small bicycle pump with guage can do the trick. I'm not sure what screw mechanism to use with pump.

 

[Joe Reeves]

Re: Johnson Seahorse '75 25hp

It's best to use a small air compressor with a long hose so as to get away from the noise. You can use a small piece of rubber fuel hose as a spacer between the screw hole and the air fitting as a seal.... OR .... design some sort of screw in fitting for a better seal.

 

[ColdPat]

Re: Johnson Seahorse '75 25hp

thanks... what about taking the screw off the bottom of the lower unit without have to drop lower unit. (turning upside down of course). I'm talking about not taking water pump housing shaft seals off.. Can I take lower unit off without doing all that

 

[F_R]

Re: Johnson Seahorse '75 25hp

You can do that, but why are you so sure it isn't the drive shaft seal and/or shift rod seal leaking also? Especially the shift rod seal, if you later decide to replace that one, you will have to redo your work you are now contemplating. It's not that much more work to just do a complete reseal job and be done with it..

 

[ColdPat]

Re: Johnson Seahorse '75 25hp

Thought if I used the ear muffs then the only water that could get in lower unit would be the shift seal and shaft seal. I thought water would go into that chamber from the water pump. The only seal left would be the prop. I was just guessing. I've takin the lower unit off before to change water pump. Just trying to save me work. signed Lazy man...