Mercury MERCRUISER, Service Manual, Page: 530 / 566

4. Connect the helm hoses to the steering cylinder as follows:
NOTE: Do not use thread sealant on the hydraulic hose connections.
a. Apply a small amount of clean lubricant to the hydraulic hose end O‑ring area.
Tube Ref No. Description Where Used Part No.
138
Synthetic Power Steering
Fluid SAE 0W-30
Hydraulic hose end O-ring area 92-858077K01
b. Push the port and starboard hoses completely into the fittings.
a - Port 90° elbow fitting
b - Starboard 90° elbow fitting
c - 90° elbow fitting O‑ring
d - Hose from the helm marked
"L‑PORT"
e - Hose from the helm marked
"R‑STARBOARD"
c. Hand‑tighten the hose fittings.
d. Make the hose connections to the steering cylinder. Use a thin wrench to keep the cylinder fittings from turning while
tightening the hoses securely. Do not overtighten the hose connections.
Initial Filling
IMPORTANT: Fill the power‑assisted steering system exactly as explained in the following procedure to ensure that all air is
bled from the system. Failure to remove the air may cause foam in the fluid during operation and discharge from the pump
reservoir. Foamy fluid may cause the power‑assisted steering system to become spongy, resulting in poor boat control.
1. Remove the cap and dipstick from the power‑assisted steering pump.
2. Add approved fluid to bring the level up to the "FULL COLD" mark on the dipstick.
IMPORTANT: Use only Synthetic Power Steering Fluid SAE 0W‑30 in the power‑assisted steering system.
Tube Ref No. Description Where Used Part No.
138
Synthetic Power Steering
Fluid SAE 0W-30
Power steering reservoir 92-858077K01
3. Install the cap and dipstick. Tighten the cap securely.
NOTICE
Without sufficient cooling water, the engine, the water pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during operation.
4. Start the engine and operate it for 10–15 seconds.
5. Stop the engine.
6. Remove the cap and dipstick from the reservoir.
7. Allow any foam in the pump reservoir to disperse.
8. Check the fluid level and add fluid as required to bring the level up to the "FULL COLD" mark on the dipstick. Do not
overfill.
9. Install the cap and dipstick. Tighten the cap securely.
10. If the fluid is still foamy, repeat steps 1–9 until the fluid does not foam and the level remains constant.
NOTE: This initial fill procedure only fills the steering helm and the pressure and tank hoses.
Purging the Hydraulic Steering System
1. Disconnect the hydraulic hoses at the steering cylinder.
2. Connect the ends of the hoses to each other using the 892526 union fitting.
c
b
c
a
d
e
43310
Compact Hydraulic Steering
Page 8B-4 © 2016 Mercury Marine 90-8M0099748 eng DECEMBER 2015