Service Manual 40-90 HP Gearcase [Gearcase Removal And Installation 2]

Gearcase Removal

To prevent accidental starting while servicing, twist and remove all spark plug leads.
During service, the outboard may drop unexpectedly. Avoid personal injury; always support the outboard’s weight with a suitable hoist or the tilt support bracket during service.

Remove pin and washer from shift rod lever to release the lower shift rod.

1. Shift rod screw

Note where the index mark on the gearcase aligns with the index number of the adjustable trim tab so the trim tab can be installed in the same position. Remove the trim tab retaining screw and trim tab from the gearcase.

1. Index mark
2. Trim tab
3. Trim tab retaining screw

Remove the 3/8-16 in. screw and washer, and remove 7/16-14 x 3.5 in. screw and washer.

O Type Gearcases

1. 3/8-16 x 3.5 in. screw
2. 7/16-14 x 3.5 in. screw

S Type Gearcases

1. 3/8-16 x 1.75 in. screw
2. 7/16-14 x 3.5 in. screw

Remove the four 3/8-16 x 1.75 in. gearcase retaining screws and washers.

1. Gearcase retaining screws

Remove the gearcase assembly from the exhaust housing, being careful not to bend the shift rod.

Gearcase Installation

During service, the outboard may drop unexpectedly. Avoid personal injury; always support the outboard’s weight with a suitable hoist or the tilt support bracket during service.

Before installing gearcase, shift rod adjustment MUST be checked. Refer to SHIFT ROD ADJUSTMENT on p. 323.

Coat the driveshaft splines with Moly Lube. DO NOT coat top surface of the driveshaft because lubricant may prevent seating of the driveshaft in the crankshaft.

Apply Adhesive 847 to the lower exhaust housing seals’ inner surfaces. Place two new seals on the housing. Apply Triple-Guard grease to the seals’ outer surfaces and place the housing on the gear case.

1. Lower exhaust seals

Slide the gearcase into place, making sure:

• Driveshaft engages the crankshaft.
• Water tube enters the water pump.
• Lower inner exhaust housing installs correctly.
• Shift rod does not turn and is positioned properly in the shift rod lever below the crankcase.

New gearcase screws are treated with a thread-locking material. Apply Triple-Guard grease to threads to ensure that the correct clamping force is achieved when tightening—If a previously installed screw is re-used, use a wire brush to remove any old thread-locking material or corrosion and lubricate threads with Triple-Guard grease.

Install screws and washers and tighten to a torque of:

• 3/8 in. screws – 26 to 28 ft. lbs. (35 to 38 N-m)
• 7/16 in. screws – 45 to 50 ft. lbs. (61 to 68 N-m)

Apply Triple-Guard grease to threads of the trim tab screw. Install and align the trim tab with the index marks noted prior to disassembly. Tighten the trim tab screw to a torque of 35 to 40 ft. lbs. (47 to 54 N-m). For adjustment, refer to Trim Tab Adjustment on p. 31.

1. Trim tab screw
2. Index mark

Place the shift rod in the shift rod lever. Install the retaining pin and washer. Tighten pin to a torque of 60 to 84 in. lbs. (7 to 9.5 N-m).

1. Shift rod screw 002013

To prevent loss of operator control, check for proper shifting operation and adjust, if necessary.

During break-in period of a reassembled gearcase, change the gearcase lubricant between 10 to 20 hours of operation.

Disassembly

Rotate the driveshaft counterclockwise to unlock the impeller key. Remove the four impeller housing screws.

1. Screws

Slide the water pump off the driveshaft. Remove the impeller key, O-ring, impeller plate, and gasket. Discard the gasket.

1. O-ring
2. Impeller plate

Remove all the parts from the housing.

Inspection

Check impeller for overheating, hub separation, and other wear or damage.

Check liner and wear plate for scoring, distortion, and impeller material transfer.

Inspect the housing for cracks or melting.

Make sure gasket surface is clean and smooth.