Lower Unit Service (Johnson 40 Motor)

Remove the cotter pin that is stuck through the propeller shaft using a pair of pliers.

Using the special wrench, loosen and remove the castle nut.

Remove the propeller.

If the washer behind the propeller did not come off with the propeller, remove it and set it aside with the propeller, other washer, and castle nut.

Remove the two screws on either side holding the anode in place using a 5/16 nut driver.

Pull the anode out

Reverse the previous steps to reinstall

Remove upper cowl by turning the black levers on the front and rear of the cowl

Remove the lower cowl by removing the one 3/8 in bolt from the front

the two 3/8 in bolts from the rear of the lower cowl

the 3/8 in bolt under the bottom of the lower cowl. This is most easily done using a universal-joint socket.

Trim the engine all the way up and pull the two halves away from the engine and downward, removing the rubber holders for the battery connection and control cables

Remove the 3/8 in screw connecting the vertical shift linkage going into the lower unit to the horizontal shift linkage in the upper unit. This Is located directly below the block on the port side of the engine.

Remove the four 9/16 in bolts connecting the lower unit to the upper unit. This will need to be done with a regular wrench.

Remove the one 5/8 in bolt holding the lower unit to the upper unit. This is located directly above the propeller. As you do this the lower unit will begin to pull away from the upper unit.

Remove the lower unit from the upper unit by gently pulling the lower unit straight away from upper unit, taking care not to bend the shaft or shift linkage.

Remove the four 7/16 in bolts holding the water pump to the lower unit

Remove the outer water pump housing by sliding it up the shaft. This should expose the inner housing.

Remove the inner housing. The impeller should be stuck tightly inside the inner housing and will come off with it.

Remove the old impeller from the housing and install the new one.

To replace the impeller and inner housing, first put the key into the notch on the shaft and slide the impeller and inner housing down the shaft lining up the key with the notch on the impeller.

Slide the housing down the shaft and make sure the seal for the outer housing is sitting in the grove on the underside of the outer housing.

To finish installation, follow the removal steps in reverse starting at step 9