Installation manual

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Boat Construction
IMPORTANT: All applicable U.S. Coast Guard reg-
ulations for INBOARD engines must be complied
with, when constructing engine compartment.
Care must be exercised in the design and
construction of the engine compartment. Seams
must be located so that any rain water or splash,
which may leak through the seams, is directed away
from the engine and carburetor cover. Also, the
passenger compartment drainage system should not
be routed directly to the engine compartment. Water
that runs on or is splashed in the carburetor cover
may enter the engine and cause serious damage
to internal engine parts.
IMPORTANT: Mercury Marine will not honor any
warranty claim for engine damage as a result of
water entry.
Engine Compartment Ventilation
Engine compartment must be designed to provide a
sufficient volume of air for engine breathing and also
must vent off any fumes in engine compartment in
accordance with industry standards (ABYC, NMMA,
etc.), federal standards and U.S. Coast Guard regula-
tions for inboard engines. Pressure differential (out-
side engine compartment versus inside engine com-
partment) should not exceed 51 mm (2 in.) of water
(measured with a manometer) at maximum air flow
rate.
Engine Compartment Specifications
Model
Engine Air Require-
ments at Wide Open
Throttle
Physical Engine
Volume*
175XR
2
487 ft.
3
/min.
(0.230 m
3
/sec.)
1.33 ft.
3
(38 L)
* Physical engine volume is used in flotation calculations and is
representative of the amount of flotation the engine provides.
For serviceability, it is recommended that an addi-
tional 152 mm (6 in) minimum (per side) of clearance
be allowed between powerhead and engine compart-
ment walls.
Exhaust System
IMPORTANT: It is the responsibility of the boat
manufacturer, or installing dealer, to properly
locate the engine. Improper installation may
allow water to enter the exhaust manifold and
combustion chambers and severely damage the
engine. Damage caused by water in the engine
will not be covered by Mercury Marine Limited
Warranty, unless this damage is the result of
defective part(s).
The engine must be properly located to ensure that
water will not enter the engine through the exhaust
system. Determine the correct engine height by tak-
ing measurements (a) and (b), with boat at rest in the
water and maximum load aboard. Subtract (b) from
(a) to find (c). If (c) is less than specified in chart, boat
construction must be altered to properly lower water-
line relative to exhaust elbow.
a
b
d
c
a - From Waterline to Top of Transom
b - From Highest Point on Exhaust Manifold to Top of Transom
c - (a) minus (b) = (c)
d - Waterline at Rest (at Maximum Load)
Model c = (a) minus (b)
175XR
2
(c) must be 203 mm (8 in.) or
more.