Mercury MerCruiser Service Manual page 62

Maintenance
Dual water pickup
NOTE: Flushing is needed only for salty, brackish, mineral laden or polluted water applications. Flushing is recommended after
each outing for best results.
Flushing the engine with the boat in the water can cause seawater to flow into the engine, resulting in engine damage. Close
the seacock before flushing the engine. Keep the seacock closed until starting the engine.
1. On models with the sterndrive seawater inlet blocked, supply water to the sterndrive and to the engine. Refer to
Alternative Water Pickups.
2. On models using the sterndrive seawater inlet and a through‑the‑hull or through‑the‑transom alternative water pickup,
supply water to only the sterndrive by taking the following steps to block, or disconnect and block, the hose from the
alternative seawater pickup pump inlet Y‑fitting.
a. If equipped with a seacock, close the seacock in the hose from the alternative water pickup.
b. If not equipped with a seacock, disconnect the hose from the alternative water pickup and plug both ends.
c. If there is not a hose running to the transom, refer to Alternative Water Pickups.
3. On models using the sterndrive water pickups for water supply: proceed to step 4 or step 5.
4. If flushing the cooling system with the boat in the water:
a. Raise the sterndrive to trailer position.
b. Install the appropriate flushing attachment over the water inlet holes in the gear housing.
c. Lower sterndrive to full down (in) position.
5. If flushing the cooling system with the boat out of the water:
a. Lower the sterndrive to full down (in) position.
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 propeller.
c. Install the appropriate flushing attachment over the water inlet holes in the gear housing.
6. Connect hose between flushing attachment and water source.
7. With the sterndrive in normal operating position, fully open the water source.
8. Place the remote control in the neutral idle speed position and start the engine.
Operating the engine out of the water at high speeds creates suction, which can collapse the water supply hose and overheat
the engine. Do not operate the engine above 1400 RPM out of the water and without sufficient cooling water supply.
9. Press the throttle‑only button and slowly advance the throttle until the engine reaches 1300 RPM (± 100 RPM).
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NOTICE
WARNING
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NOTICE
© 2016 Mercury Marine
5773
Side water pickup
90-8M0099748 eng DECEMBER 2015