Where does the driveshaft O-ring go? 1980 Evinrude 7.5

[Todd in NY]

I replaced the impeller on my 1980 long shaft 7.5 Evinrude, and my Clymer shop manual does't show me where to place the new driveshaft O-ring. When I disassembled the lower unit the O-ring was near the top of the driveshaft near the bottom of the upper splines. But there is no groove in the driveshaft for the O-ring. Does the O-ring go toward the top of the driveshaft or does it go under the impeller cup in the impeller housing? I don't want to assume that the O-ring goes on the top section of the driveshaft just because it was there when I disassembled the motor, because what if it was assembled wrong by the previous owner?

Does anyone know where this driveshaft O-ring should be installed? Thanks in advance!

 

[Vic.S]

I expected there to be a groove for it immediately below the splines but according to the Seloc manual it slides down the drive shaft until it is in place on the top of the water pump.
Are you sure there's no grove below the splines because i am puzzled by what its purpose is if it's not up there.

See the last paragraph (31) on this page, continued on the next.

http://boatinfo.no/lib/evinrude/manu...rude.html#/346

 

[interalian]

I had an '82 7.5 Evinrude and remember it had a groove for the o-ring just below the splines.

 

[Todd in NY]

Well, I had a very frustrating day with this 7.5, and it's all my fault. I took this motor apart almost a year ago with a friend of mine. He had brought over his long shaft parts to give to me for another friend and without realizing it, we got our drive shafts mixed up. His drive shaft was with my parts and my drive shaft was in a random place in my garage, not it plain sight (aka BURIED).

Bottom line is, the CORRECT Evinrude 7.5 drive shaft does HAVE a groove at the top for the O-ring, and it has four splines. The Johnson drive shaft that I unknowingly assembled my motor with is about a half inch shorter and has 6 or 8 splines at the top. When it didn't start pumping water right way I shut down the motor and tore my garage apart, finally realizing that the only thing that could have gone wrong is the drive shaft not being the correct one.

I finally found my Evinrude drive shaft but now I have to go to the dealer tomorrow and hope that he has the parts I need to put my motor together again. I don't remember how the drive shafts got mixed up, but I was kicking myself real hard earlier today when I figured it out.

Thanks for all the replies and the reference material!!!

 

[interalian]

Another lesson learned.

My wife was amazed I was able to tear two V-4s apart, have the parts strewn across three benches and the two stern decks of the boat AND the motor well, and still be able to put it all together to make a running motor.

 

[Todd in NY]

I was going to convert my motor to a short shaft by trading short shaft parts for my long shaft parts with the 3rd friend I mentioned. For whatever reason, the parts swap never happened. I think he had everything but the water tube. My motor looks great for its age and runs great, so I decided to buy a mini jacker plate and just keep my motor. I fish on several lakes that have a 10hp max restriction and this 7.5 is just too good a motor to part with. Plus it really sips the gas.

Very nice to be able to keep track of two motors worth of parts and not screw something up!

 

[interalian]

Very nice to be able to keep track of two motors worth of parts and not screw something up!

Well, I only ended up with one running motor. And a bunch of spare parts and a hundred bucks back from the scrap aluminium... :laugh:

 

[Todd in NY]

Still not a bad deal. Scavaging parts is sort of an art form. You have to know what is usable and what's not.