Mercury MERCRUISER, Service Manual, Page: 63 / 566

10. Observe the water temperature gauge to ensure that the engine is operating in the normal range.
11. Operate the engine with the sterndrive in neutral for about 10 minutes or until the discharge water is clear.
12. Slowly return the throttle to idle speed position.
13. Stop the engine.
14. Shut off the water and remove the flushing attachment.
15. Remove the seawater inlet hose from the seawater pump and plug the hose to prevent water from siphoning into the
engine.
16. Tag the ignition switch with an appropriate tag requiring the seawater inlet hose to be reconnected prior to operating the
engine.
Alternative Water Pickups
IMPORTANT: Two water sources are needed for this procedure.
NOTE: Flushing is needed only for salty, brackish, mineral‑laden or polluted water applications. Flushing is recommended after
each outing for best results.
IMPORTANT: Models with the sterndrive water inlet blocked off at the gimbal housing and using a through‑hull water inlet need
a supply of cooling water available to both the sterndrive and to the engine during operation.
1. If flushing the cooling system with the boat in the water:
a. Raise the sterndrive to the trailer position.
b. Install the appropriate flushing attachment over the water inlet holes in the gear housing.
c. Lower the sterndrive unit to the full down (in) position.
2. If flushing the cooling system with the boat out of the water:
a. Lower the sterndrive to the full down (in) position.
!
WARNING
Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed.
Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the
engine from starting. Place a block of wood between the propeller blade and the anti‑ventilation plate.
b. Remove the propeller. Refer to the appropriate sterndrive service manual for details.
c. Install the appropriate flushing attachment over the water inlet holes in the gear housing.
3. Connect a hose between the flushing attachment and a water source.
4. Close the seacock, if equipped, to prevent water from siphoning into the engine or boat.
5. Remove the seawater inlet hose from the seawater pump at the location shown. Plug the hose to prevent water from
siphoning into the engine or boat.
33208
Seawater inlet hose connection
6. Using a suitable adapter, connect the flushing hose from the water source to the water inlet of the seawater pump.
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.
Maintenance
90-8M0099748 eng DECEMBER 2015 © 2016 Mercury Marine Page 1C-47