Alternative Water Pickups - Mercury 350 MAG Manual

Section 5 - Maintenance
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 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 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 sterndrive in normal operating position, open the water source fully.
8. Place the remote control in the neutral idle speed position and start 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. Depress the throttle‑only button and slowly advance the throttle until the engine reaches 1300 RPM (± 100 RPM).
10. Observe the water temperature gauge to ensure that the engine is operating in the normal range.
11. Operate engine with sterndrive in neutral for about 10 minutes or until discharge water is clear.
12. Slowly return throttle to idle speed position.
13. Stop engine.
14. Shut off water and remove 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 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 sterndrive to trailer position.
b. Install the appropriate flushing attachment over the water inlet holes in the gear housing.
c. Lower sterndrive unit to full down (in) position.
2. If flushing the cooling system with the boat out of the water:
a. Lower 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.
3. Connect hose between flushing attachment and water source.
4. Close the seacock, if equipped, to prevent water from siphoning into the engine or boat.
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WARNING
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NOTICE
WARNING
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90-8M0050539 MAY 2011
eng