Johnson 15 lower unit will not go on.

[thatone123]

I have never seen this problem and have put many lower units on these 15's. Changed the water pump, no big deal but LU will not go back on. The drive shaft will not go into the splined female shaft at bottom of motor. What seems strange is when I shine a light up there I don't see a female splined shaft. Something is up there but the distance up the shaft tunnel is too far to see to make it out. This is a typical mid-80's model that has had some salt usage. Never have seen this problem before.

 

[GA_Boater]

Did you grease the splines? Too much and the excess causes this. Kinda like a hydrolock.

Just tossing ideas.

 

[flyingscott]

What yr exactly. Does it have a a slot for the o ring? Did it come out with the shaft? Or is it the newer style without the o-ring? Did one of the seals slip?

 

[thatone123]

Yes, Greased the splines after this happened and the same. Yes, O ring on top, but it did not have one when taken out. IT had the slot around the shaft so I thought the last person taking it apart just did not put it in. I will go try it without the O ring.

 

[thatone123]

Well, Goleee, that was it FS...Thanks for reminding me of my short time memory loss> What I was seeing was the grease around the female motor drive shaft opening that made it look weird. Once I took off the O ring it went on perfectly! I guess the drive shafts continued to have the slot for the O ring...Now I know.

 

[flyingscott]

You need to check the model yr of your motor! If it has the guide with 2 seals on it you are fine. If it has one seal you need the oring on it. There is a chance somebody replaced your driveshaft. They did not use the grooved drive shaft in the newer models with the 2 seals.