GASOLINE ENGINES BRAVO MODELS
Page 11 of 116
ENGINE COMPARTMENT
WARNING
Boating standards (NMMA, ABYC, etc.) and Coast Guard regulations must be ad-
hered to when constructing the engine compartment.
Care must be exercised in the design and construction of the engine compartment. Seams
must be located so that any rain water, which may leak through the seams, is directed away
from the air intake system. Water that runs onto the air intake may enter the engine and
cause serious damage to internal engine parts.
Over the last several years, engine compartments have been designed to be quieter. The
most common material used to deaden the engine sound is some type of insulation material.
Normally, the quieter the engine compartment is, the more insulation material used which
results in less air space inside. The less air space inside the engine compartment, the hotter
the inside air temperature. Attention must be given to the air temperature that is inside this
engine compartment while the engine is running or after a period of time after the engine
is shut off (heat soak). Refer to the following information on Engine Compartment Ventila-
tion.
ENGINE COMPARTMENT VENTILATION
General Information
According to Boating standards (NMMA, ABYC, etc.) and Coast Guard regulations the en-
gine compartment ventilation system has multiple tasks. Included are the following:
1. To supply the engine with combustion air.
2. To maintain a low temperature in the engine compartment.
3. To vent the air and fumes in the engine compartment.
Fresh air should enter the engine compartment as low as possible and the heated air should
be discharged from the highest point.
When sufficient ventilation is not provided, too much heat can build-up inside of engine
compartment and cause vapor locking. The engine will not want to restart after it has been
shut off for a short period of time. If it does restart, the engine will quit when given the throttle
to get the boat up on plane or to pull up a water skier.
For engines utilizing fuels containing alcohol and the newer “reformulated gasolines” (See
OEM Service Bulletin 95-2.) proper ventilation is more critical to prevent vapor locking.
If a separate air shaft (or similar) is used to provide engine compartment ventilation or addi-
tional ventilation, care must be taken to prevent seawater and spray from entering it.
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