GASOLINE ENGINES SKI MODELS
Page 8 of 48
Compartment Temperature - Specifications
Air temperatures inside of engine compartments have been measured in excess of 200
°
F
(82
°
C). The long term effect to fuel system components running at these excessive temper-
atures is not known at this time.
According to specification SAE J1223 for Marine Carburetors:
“The carburetor shall be capable of operation throughout an ambient (air temperature)
range from +20
°
to +176
°
F (–7
°
to +80
°
C) without failure.”
Carburetors, throttle body injection (TBI) units and components for multi-port EFI systems
used by MerCruiser meet this specification.
Under the hottest outside air temperature condition at which the boat will be operated, the
air temperature inside the engine compartment, measured at the flame arrestor, shall not
exceed 176
°
F (80
°
C). Also, the temperature of the fuel being supplied to the engine shall
not exceed 110
°
F (43
°
C) at any location between the fuel tank and the engine’s fuel pump.
Since many factors influence engine compartment temperature, temperature measure-
ments should always be carried out as follows.
Compartment Temperature - Testing
Test as follows:
1. The boat being tested shall be a standard production boat fitted as it would be for
delivery to a dealer.
2. Temperature test meter used shall be of the type that can be read without opening the
engine cover.
3. During the test, in Step 4, engine compartments are to remain closed. No outside air is
to be forced into the engine compartment during the test and the bilge blower should not
be running.
4. Engine Running and Heat Soak Test:
a. Use 1 meter and 2 thermal couples. Place one thermal couple at the flame arrestor
to measure the inlet air temperature. Place the second thermal couple at the fuel
pump to measure the inlet fuel temperature. A third thermal couple is needed if the
fuel supply line between the tank and the fuel pump is higher than the fuel pump.
Place the third thermal couple at the highest point of the supply line to measure the
temperature of the fuel at that point.
b. Start engine to warm it up. After engine is at its normal operating temperature, run
engine at 1500 rpm (in neutral gear) for 15 minutes. Record both temperature read-
ings at 5 minute intervals.
c. After 15 minutes running at 1500 rpm, shut engine off and continue to record both
temperature readings at 5 minute intervals for the next 45 minutes.
d. After the 45 minute heat soak test, start engine and idle (in neutral gear) for 20 min-
utes. Continue to record both temperature readings at 5 minute intervals.
IMPORTANT: If the temperature at either location exceeds specifications, the engine
compartment will need additional ventilation until both temperatures remain below
these specifications.