Operating In Freezing Temperatures; Operating In Saltwater Or Polluted Water; Prestarting Instructions - Mercury 40 FourStroke Maintenance And Installation Manual

Operating in Freezing Temperatures

When using your outboard or having your outboard moored in freezing or near
freezing temperatures, keep the outboard tilted down at all times so the
gearcase is submerged. This prevents the trapped water in the gearcase from
freezing and causing possible damage to the water pump and other
components.
If there is a chance of ice forming on the water, the outboard should be
removed and drained completely of water. If ice should form at the water level
inside the outboard driveshaft housing, it will block water flow to the engine
causing possible damage.

Operating in Saltwater or Polluted Water

We recommend that you flush the internal water passages of your outboard
with fresh water after each use in salt or polluted water. This will prevent a
buildup of deposits from clogging the water passages. Refer to Maintenance ‑
Flushing the Cooling System.
If you keep your boat moored in the water, always tilt the outboard so the
gearcase is completely out of water (except in freezing temperatures) when not
in use.
Wash the outboard exterior and flush out the exhaust outlet of the propeller and
gearcase with fresh water after each use. Each month, spray Mercury Precision
or Quicksilver Corrosion Guard on external metal surfaces. Do not spray on
corrosion control anodes as this will reduce the effectiveness of the anodes.

Prestarting Instructions

1. Check the engine oil level.
2. Make sure the cooling water intake is submerged.
OPERATION
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