Operating In Saltwater Or Polluted Water; Operating At High Elevations; Setting Trim Angle While Running Engine At Idle Speed - Mercury 200 OptiMax DTS Manual

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.

Operating at High Elevations

Your engine automatically compensates for high elevation
changes. A different pitch propeller may help reduce some
normal performance loss resulting from reduced oxygen in the
air. Consult your dealer.
Setting Trim Angle While Running Engine at Idle
Speed
Submerging the exhaust relief hole on the outboard can happen
on some boats if you trim full in while running at idle speed,
resulting in, exhaust restriction, rough idle, excessive smoke,
and fouled spark plugs. If this condition exists, trim outboard up
until exhaust relief hole is out of the water.
a
eng
OPERATION
b
2729
101
a - Relief hole
submerged (wrong)
b - Relief hole above
waterline (correct)