Mercury MerCruiser Service Manual page 525

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.
2.
If the boat is out of the water, connect a flush test device to the sterndrive. Refer to Seawater System for proper seawater
supply procedures. The cooling system is full when water is discharged through the propeller.
NOTE: For complete flush test device installation instructions, refer to Sterndrive Water Pickups in Section 1C .
3. Start the engine and operate it at 1000–1500 RPM until it reaches normal operating temperature.
4. Close the test gauge valve briefly to obtain a maximum pressure reading.
5. Cycle the test gauge valve open and closed three times, and record the highest pressure reading attained during each
cycle.
a. If the pressure readings are 7932–8621 kPa (1150–1250 psi) and are within 345 kPa (50 psi) of each other, then the
pump is within specifications. If the pump is within specifications, but system pressure was low (as tested under the
Power‑Assisted Steering System Pressure Test), refer to the appropriate Mercury MerCruiser sterndrive service
manual for additional information.
b. If the pressure readings are 7932–621 kPa (1150–1250 psi), but are not within 345 kPa (50 psi) of each other, then
the steering pump flow control valve is sticking or the pump hydraulic system is dirty. Flush the pump with clean
power steering fluid and recheck the pump pressure. If pump pressure is still not within specification, replace the
power‑assisted steering pump.
c. If pressure readings are constant, but below 6897 kPa (1000 psi), replace the power‑assisted steering pump.
90-8M0099748 eng DECEMBER 2015
Power-Assisted Steering Pump and Related Components
NOTICE
Bravo drive with flush test device
© 2016 Mercury Marine
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