Nissan 15 hp lower unit removal

bluwtr

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Jun 3, 2007
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18
I need to pull my lower unit to replace the impeller. I've removed the four nuts and the shift linkage pins. The unit will not drop-- the back side is free but not the front. The parts diagram shows a stud possibly in the front but I can't find it. Anyone able to solve my mystery?!?!
 

pvanv

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Apr 20, 2008
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First, we need your actual model.
You only need to pull one pin from the cam rod.
There are 4 studs; one for each nut.
Odds are the drive shaft splines are stuck in the crank shaft. Wedges and patience will get it out.
Don't replace just the impeller; do a complete wp kit; works better, and lasts longer.
 

Sea Rider

Supreme Mariner
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Sep 20, 2008
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Plastic or wooden wedges and patience are needed to pull lower leg down. Grese lightly drive shaft splines when assembling back lower leg, next time will be much easier to remove than before.

Happy Boating
 

bluwtr

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Jun 3, 2007
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18
It's a NS15D2. Mine doesn't have bolts. It just has four nuts and washers. I just found a small (5/16" maybe) bolt under the shift linkage. Problem is there is no way that I can find to remove it. The bolt head sits just under a lip in the lower unit and the secondary shift linkage rod is in the way. I will get a picture to show more detail.

I actually bought the impeller, cup, plat and o-ring.
 

bluwtr

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I'm not sure what's going on. The system won't let me upload any photos. It told me they were too large, so I cropped them and made them under the 2 MB size. Not it's telling me they are larger than the 4 KB size or such. WTC?
 

pvanv

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That bolt is irrelevant. There are 4 nuts on 4 studs (and of course the shift linkage), and that is all.
002-21043-4_FIG08.JPG
 

pvanv

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The bolt you are showing is for the stopper for the cam rod. Item 8 in the drawing. 002-21043-4_FIG10.JPG
 

bluwtr

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Jun 3, 2007
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I missed what you said about #8. That's good to know. What can you tell me about #26? Is it just a "guide" stud?
 

Sea Rider

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26 is a rubber tube which has another large one inside it, drawing doesn't shows it, shift rod passes through it, keeps water from entering pan. Only need to remove upper pin from coupler.

Happy Boating
 

bluwtr

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Jun 3, 2007
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Not trying to beat a dead horse, but according to my repair manual #26 is a"stud bolt" I just have to be sure because I sure can afford a new motor. :)
 

bluwtr

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No Title

Here's what my manual says/shows.
 

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Sea Rider

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Sep 20, 2008
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Sorry number 25 corresponds to post 8. Newer lower leg units are like this one, does not show part 26 whatsoever. It's as simple as removing upper coupler pin and 4 lower bolts and that's it..

Lower Leg.JPG

Assume that never before have stripped a lower leg, it that's so, your whole issue is a seizure between drive shaft (Yellow X)


DSCF7018.JPG

And Lower Crank Shaft (Red X)

Lower Crank Shaft.JPG

Insert a plastic or wooden wedge at both lateral sides of both mating surfaces and bang with a rubber mallet hammer each side gently till lower unit falls. Patience and good humor is key...

Happy Boating
 

bluwtr

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Jun 3, 2007
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Ok and thanks. I'll just fight it loose with the wedges. As you can imagine, I didn't want to risk breaking something if there was the stud that I asked about.
 

bluwtr

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Jun 3, 2007
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Got it off! After studying the diagrams closer (zoomed in more) I realized that the #26 stud are just the four studs that the nuts pull the LU to the drive shaft housing. I decided that something had to give so I got a little more aggressive with my hammer blows. Used screw drivers, plastic wedges and a LOT of penetrating oil. Got the LU off, pulled the water pump parts and replaced all with new. The old parts were in pretty good shape so I saved them for emergency spares.

Thanks for all of the help.
 

Sea Rider

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Sep 20, 2008
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Good to read that finally it worked for you, don't forget to apply a light coat of marine grease preferably on upper drive shaft splines, that way won't seize into lower crank shaft, future lower leg removal will be a breeze...

Happy Boating
 
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