Using Oxygenated Fuels or
Fuels with Alcohol
MBTE (methyl butyl tertiary ether) is an oxygenate and
octane enhancer. This compound may be blended with
fuel. Fuel that is no more than 15% MBTE is acceptable
for use in the Indmar engine.
Ethyl alcohol, ethanol or grain alcohol is acceptable as
long as it is a blend and the blended fuel contains no
more than 10% ethanol.
Fuels in Other Countries
If the Indmar-equipped boat is operated outside the USA
or Canada, unleaded fuels may be difficult to obtain.
Leaded fuels are not recommended as engine compo
-
nents will last longer using unleaded fuel.
Crusader Engines
The following information applies to boats equipped with
Crusader Engines:
The ignition timing set by the factory requires the use of a
high-quality, lead-free regular gasoline with the following
octane specification:
Pump Octane Number (R+M/2) (PUMP) – 87
NOTICE: Most Crusader fuel-injected engines are
calibrated to operate on 87 octane fuel, and maxi-
mum performance is obtained when using this fuel.
Some applications may require a higher octane fuel.
If a slight pinging is heard during acceleration and the
proper octane fuel is being used, it is considered normal.
If a constant, heavy knock occurs, the engine should be
evaluated by an authorized MasterCraft service techni-
cian.
Gasoline Containing Alcohol
Ethanol blended fuel rated E10 or less is acceptable
to use. Fuels rated higher than E10 SHOULD NOT BE
USED. Ethanol fuels rated higher than E10 could po-
tentially damage the engine and/or present an unsafe
boating condition. Damage to the engine resulting
from the use of ethanol fuel rated higher than E10 IS
NOT covered by the warranty.
Do not use any gasoline that contains METHANOL.
This fuel is very corrosive and will create unsafe op-
erating conditions. Serious damage will result from
the continued use of fuel containing METHANOL.
Any resulting engine damage will not be covered by
the warranty.
If ethanol-blended fuel rated E10 or less is used, or if
the presence of alcohol is uncertain, more frequent in-
spections and service of the complete fuel system are re-
quired. Any sign of fuel leakage or deterioration must be
repaired immediately before further engine operation.
It is important to note that enthanol-blended fuel will act
as a solvent and will attract and hold moisture.
Without
proper fuel stabilization and fuel filtration, ethanol
blended fuel may cause the following:
• Excessive moisture (water) may cause lean operation
to include hard starting and operating difficulties such
as: vapor lock, low speed stalling, and shortened fuel
shelf life.
• Acting as a solvent, ethanol blended fuel may cause
gum, sediment, sludge, and other particles to be loos-
ened and carried through the fuel system to the engine.
Fuel system or engine damage caused by contami-
nation from water, foreign particles, sludge, or gums
entering or forming in the fuel system is not covered
by the Crusader Limited Warranty.
NOTICE: Some gasolines contain an octane-enhanc-
ing additive called methylcyclopentadlenyl manga-
nese tricarbonyl (MMT). These should not be used.
These fuels may reduce spark plug life, and engine
performance may be affected.
2008 MasterCraft Owners Manual Page 6-2