After Each Use; Every 100 Hours Of Use Or Once Yearly, Whichever Occurs First; Before Periods Of Storage; Submerged Outboard - Mercury FourStroke 2.5 Service Manual

After Each Use

• Flush out the outboard cooling system if operating in salt or polluted water. See Flushing the Cooling System.

Every 100 Hours of Use or Once Yearly, Whichever Occurs First

• Lubricate all lubrication points. Lubricate more frequently when used in saltwater. 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 the spark plug every 100 hours or once yearly.
Replace the spark plug as needed. See Spark Plug Inspection and Replacement.
• Drain and replace gearcase lubricant. See Gearcase Lubrication.
• Check corrosion control anode. Check more frequently when used in saltwater. See Corrosion Control Anode.
•
Check and adjust valve clearance, if necessary.
•
Lubricate splines on the driveshaft.
•
Replace water pump impeller.
• Check tightness of bolts, nuts, and other fasteners.

Before Periods of Storage

• Refer to Storage procedure. See Storage section.

Submerged Outboard

A submerged outboard will require service within a few hours by an authorized dealer once the outboard is recovered from the
water. This immediate attention by a servicing dealer is necessary once the engine is exposed to the atmosphere to minimize
internal corrosion damage to the engine.

Exterior Care

Your outboard is protected with a durable baked enamel finish. Clean and wax often using marine cleaners and waxes.

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.
Use a Mercury Precision or Quicksilver accessory (or equivalent) flushing attachment.
NOTE: Do not run the engine while flushing the cooling system.
1. Remove the plug and gasket.
2. Attach the hose coupling to the engine.
3. Attach a water hose to the hose coupling. Turn on the water gently and flush the cooling system for 3 to 5 minutes.
4. Turn the water off. Remove the hose coupling and reinstall the plug and gasket.
b
a
1. These items should be serviced by an authorized dealer.
90-8M0065421 NOVEMBER 2012
1.
1.
1.
a - Plug and gasket
b - Hose coupling
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Maintenance
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