Evinrude 9.5hp Lower Unit Gearcase Rebuild – Part 3

Final Assembly

So far I’ve gotten the unit torn down, the seals and bushings replaced and installed the shift rod and the impeller. Now it’s time to get on to the final assembly and testing. I’ll be focusing on the lower unit gearcase. Let’s get on with installing the gears, sealing the unit up and give a test.

Assembling the Lower Unit Gearcase

Setting the Gears in

Pinion Gear set on Drive Shat

The next step in rebuilding this lower unit is to set the gears in place. After carefully inspecting all of the drive components I cleaned and gave them all a nice coat of 30 weight oil. I prefer to coat them in oil so that there is some lubrication between all parts. This avoids any dry areas when first starting, before the lower unit oil has a chance to work it’s way in to all the moving parts and bearings. In this picture you can see the pinion gear set into place on top of the Drive shaft.

As you can see in the above picture, the shifter lever has been put in place on the shift rod and subsequently flipped backwards, therefore making it easier to put the gear assembly in.

Front Bearing Slot Must Face Down When Installing
Gear Case Head and Bearing - Tab must face down when Installing

Gear Assembly – Aligning the Bearings

Lower Unit Gears in Place Shifter Lever inserted into Clutch Dog

It is important to make sure that the front bearing and Gear Case bearing are correctly aligned. The front bearing (pictured above on left) must have the slot facing down when installing. The Gear case head must have the tab on it facing down as well (See picture above on right). This insures that the lower unit oil will flow on to the bearing surfaces when operating the motor.

After making sure everything is aligned correctly, I placed the gear assembly into place on the lower unit. At this point, I placed the cradle shifter on to the clutch dog and  then insterted the ears on the shift lever on to the the tabs in the cradle shifter.

Sealing the Lower Unit Gearcase

Before sealing the lower unit, I test fit the skeg onto the gear case. I wanted to make sure everything fit correctly. Nothing would be worse than having gasket sealant on everything and there was an aliment problem. After insuring that everything fit correctly, I started applying the permatex gasket sealer.

Starting with the gear case, I applied a thin film of the permatex gasket sealer around the perimeter and the well where the gear case sets into. See the picture below on left. At this point, I placed the gears back into place. Next I applied the gasket sealer to the skeg. Put the sealer all around the edge, where the spaghetti gasket will sit as well as to the well where the gear case head will sit. Placing the spaghetti gasket in place and leaving about an 1/8″ protruding on both ends prepared it for the final install. See the picture below on the right.

Permatex Applied on Gear Housing
Permatex Applied on Channel for Spaghetti Gasket

Final Steps

Now that I had the gasket it place, I carefully placed it on the gear housing. I set the two middle screws in place (picture on below on left) and snugged them in. I inserted the pivot screw in the side after carefully checking that the hole in the shift lever was correctly aligned (Below picture on right). The next step was to test everything before completely sealing the unit. I tested the gears by turning the drive shat (clockwise) and shifting from Forward to Neutral and finally reverse.

Installing Screws on Skeg
Lining up Pivot Screw

Subsequently, after ensuring that everything worked correctly I finished sealing the unit up. Installing the final four screws and tightening them up finished sealing the gear case. I tightened both of the middle screws first.Next, I tightened the four screws on the outside working my way through them in an X pattern.

The final steps were to put the Drive pin on the shaft and then installing the propeller, the prop nut and the cotter pin. The lower unit gearcase is complete.


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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