Evinrude 9.5hp Lower Unit Rebuild – Part 1

1971 9.5hp Evinrude on Back of Boston Whaler

Removing the Lower Unit

Dropping the lower unit was fairly simple. There are four bolts holding it in place. There is also a shift rod connector that you have to take into account to completely release the lower unit. If you look at the  pictures below you can see the Brass connector on the far left, the middle picture shows you a general location.

The picture at the far right is the top of the shift rod that is inserted into the connector. This is held together by tightening the bottom screw on the connector. Ordinarily, you would put the unit in forward gear to lower the shift rod as much as possible. This will usually give you reasonable access to the screw to disconnect the lower shift rod. However, in our case, the shifter was stuck in neutral. As a result, we had to had to work in a more confined area to disconnect it. Luckily, we finally got it off.

9.5_Evinrude Shift Rod connector
Shift Rod Connector
9.5_Evinrude Shift Rod Connector Location
Shift Rod Connector Location
9.5_Evinrude Lower Shift Rod
Lower Shift Rod - The slotted tip fits into the bottom of the connector on the left. Tightening the bolt locks it in place

Disassembling the Lower Unit

To dissemble the unit I placed it upside down in an old Craftsman clamping workbench. If you work on your own lower units, these benches are indispensable! You’ll have to take the prop off first. Remove the cotter pin from the prop nut, spin off the prop nut and remove the drive pin. The prop will slide right off.

Once those are off you will have to remove the six screws holding the skeg on to the housing. I was relatively lucky, these screws came out easily. It is quite common to have to use an impact tool to remove these screws. Once these are off you’ll have to remove one more screw to get the skeg off.

On the side of the skeg, there is a pivot pin. See middle picture below. The pivot pin provides a pivot point for the shifter lever. In turn this moves the shifter cradle which slides the clutch dog to revers, neutral or forward. Here is a link to a diagram of these components. In any event, be extremely careful to not lose or break any of these. Some of the replacement parts are ridiculously expensive, if you can even find them!

Evinrude Johnson Lower Unit Skeg Screws
Removing Lower Unit Skeg Screws
Lower Unit Rebuild Pivot Screw
Lower Unit Pivot Screw
Lower Unit, Gears, Shift Leverl, Cradle Shifter and Clutch Dog
Lower Unit Gear Assembly

Stuck Shift Rod

When examining the lower unit, I discovered that the shift rod was stuck. To clarify, the shift rod was completely frozen. I removed the gear assembly from the housing and went after the shift rod. There was no amount of pushing, twisting or pulling that would get the shift rod to move. I resorted to using a hammer and a block of wood. Applying “Free All” penetrating oil to both sides of the shift rod helped in loosening the rod. I used a block of wood to prevent damage to the shift rod. Using a hammer, I slowly beat the rod out.

The rod itself looked to be in good overall condition. But i did find that there was a slight bend in the rod. The shift rod should be straight. Fortunately, I was able to straighten the rod out using a bench vise and gently pulling on the rod to straighten the rod out. If you have a flat surface, you can roll the rod and see where the rod needs straightening. In this case, I marked the rod at the center of the bend with a sharpie to guide me in the straightening process.

The shift rod bushing seemed in good shape. However, the o-ring was pretty chewed up. The bushing seemed to be in decent shape but to be sure, would probably get a bit beat up when removing it. I went ahead and ordered replacement bushing and O-ring. See the pictures below for how they looked. I’ll describe the removal process I used in part 2.

Lower Unit housing Shift Rod Bushing
Shift Rod Bushing (Note that Seal housing has already been removed in this picture)
Lower Unit Shift Rod Seal
View of shift rod o-ring from gear side of the housing. The o-ring looks pretty chewed up
Shift Rod o-ring and Bushing
Shift Rod o-ring and bushing after removing them.

Water pump and Gear Assembly

The gear assembly came out easily. It was simply a matter of lifting it out. I also removed the pinion gear and set it aside. At this point I turned the unit right side up and removed the four screws holding the impeller housing in place. I removed the housing, impeller, impeller plate and the bearing housing.

The bearing housing was a bit difficult to remove. When installed, there is a gasket between it and the lower part of the gear housing. With this in mind, I used a screwdriver to carefully work my way around it. Gently prying just a fraction of an inch at a time.

Eventually it gave, so I continued prying moving in a clockwise fashion around the housing until it finally lifted free. I was sweating bullets on this one, you could see the lower unit housing flexing just a little bit when prying on the bearing housing. Being cautious with this part of the disassembly is an understatement.

 

Lower Unit Removing the Bearing Housing
Gently working the screwdriver around the bearing housing
Gently working the screwdriver around the lower unit bearing housing
Slowly but surely, lever the bearing housing loose

Now that the lower unit is completely disassembled I can complete the lower unit rebuild. I’ll be changing all the seals. Additionally, the water pump/impeller and gaskets will be replaced. In any event, read about this in Part 2.

I have to give a ton of credit to “Rocket City Motors” on Youtube. In the meantime, If you prefer a video tutorial on how to do a lower unit rebuild I would highly recommend these videos. I used many of his techniques to complete my lower unit rebuild.

Watch the Entire Rebuild on YouTube below

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