Mercury 15 EFI FourStroke, Service Manual

Page: 334 / 406

IMPORTANT: Install the pinion nut with the step side of the nut against the pinion gear.
a - Pinion gear
b - Pinion nut
c - Step side (install toward pinion gear)
4. Use the driveshaft holding tool and a suitable wrench to tighten the pinion nut to the specified torque.
a - Pinion gear
b - Pinion nut
Driveshaft Holding Tool 91‑804762
Tube Ref No. Description Where Used Part No.
7
Loctite® 271
Threadlocker
Pinion nut threads 92-809819
Description Nm lb‑in. lb‑ft
Pinion nut 35 – 25.8
Forward Gear Backlash
NOTE: There are no shims behind the forward gear bearing assembly. Forward gear backlash is changed by adding or
subtracting shims located between the lower water pump base and the upper driveshaft bearing. Adding shims reduces
backlash, removing shims increases backlash.
1. Secure the gearcase in a vise or gearcase holding fixture. The driveshaft must be kept vertical to provide the most
accurate measurements.
NOTE: Verify the shims are installed above the upper driveshaft bearing before installing the water pump base.
2. Place the water pump base gasket on the gear housing, slide the water pump base down the driveshaft, and seat the base
into the gear housing.
3. Install the water pump guide plate gasket and water pump guide plate.
4. Secure the water pump base assembly to the gearcase with four M6 x 1 screws (obtain locally). Tighten the screws to the
specified torque.
Description Nm lb‑in. lb‑ft
Screw (M6 x 1) 6.0 53.1 –
a
b
c
7378
a
b
7394
Gear Housing (2.15:1)
90-8M0125265 eng NOVEMBER 2017 © 2018 Mercury Marine Page 6A-33