Inspection And Maintenance Schedule; Flushing The Cooling System - Mercury 40 Operator's Manual

The owner/operator is not to modify the engine in any manner that would alter the horsepower or allow emissions
levels to exceed their predetermined factory specifications.

Inspection And Maintenance Schedule

BEFORE EACH USE
• Check engine oil level. See Fuel & Oil ‑ Checking and Adding Engine Oil.
• Visually inspect the fuel system for deterioration or leaks.
• Check outboard for tightness on transom.
• Check propeller blades for damage.
AFTER EACH USE
• Flush out the outboard cooling system if operating in salt or polluted water. See Flushing the Cooling
System.
• Wash off all salt deposits and flush out the exhaust outlet of the propeller and gearcase with fresh water if
operating in salt water.
EVERY 100 HOURS OF USE OR ONCE YEARLY, WHICHEVER OCCURS FIRST
• Lubricate all lubrication points. Lubricate more frequently when used in salt water. See Lubrication Points.
• Change engine oil. The oil should be changed more often when the engine is operated under adverse
conditions such as extended trolling. See Changing Engine Oil.
• Replace spark plug at first 100 hours or first year. After that, inspect spark plug every 100 hours or once
yearly. Replace spark plug as needed. See Spark Plug Inspection and Replacement.
• Drain and replace gearcase lubricant. See Gearcase Lubrication.
• Check fuel line filter for contaminants. See Fuel System.
• Check corrosion control anode. Check more frequently when used in salt water. See Corrosion Control
Anodes.
•
Lubricate splines on the driveshaft.
•
Replace water pump impeller.
• Check tightness of bolts, nuts, and other fasteners.
• Check cowl seals to make sure seals are intact and not damaged.
• Check internal cowl sound reduction foam (if equipped) to make sure foam in intact and not damaged.
• Check that the intake silencer (if equipped) is in place.
• Check that the idle relief muffler (If equipped) is in place.
• Check for loose hose clamps and rubber boots (if equipped) on the air intake assembly.
BEFORE PERIODS OF STORAGE
• Refer to Storage procedure. See Storage section.

Flushing The Cooling System

Flush the internal water passages of the outboard with fresh water after each use in salt, polluted, or muddy water.
This will help prevent a buildup of deposits from clogging the internal water passages.
IMPORTANT: The engine must be run during flushing in order to open the thermostat and circulate water through
the water passages.
To avoid possible injury when flushing, remove the propeller. Refer to Propeller Replacement.
1. These items should be serviced by an authorized dealer.
MAINTENANCE
1.
1.
WARNING
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