Filling The Tank; Phase Separation; Additives; Fuel Filters - Boston Whaler Montauk 190 Owner's Manual

Section 3 • Systems & Components Overview & Operation
or replaced that are not recommended by Boston
Whaler, Mercury or may not be ethanol-compatible.

Filling The Tank

It is best to maintain a full tank of fuel when the
engine is not in use. This will reduce air flow in and
out of the tank due to changes in temperature as
well as limiting exposure of the ethanol in the fuel
to humidity and condensation.

Phase Separation

Humidity and condensation create water in your fuel
tank which can adversely effect the ethanol blended
fuel. A condition called phase separation can occur
if water is drawn into the fuel beyond the saturation
point. The presence of water in the fuel beyond the
saturation level will cause most of the ethanol in the
fuel to separate from the bulk fuel and drop to the
bottom of the tank, significantly reducing the level of
ethanol in the fuel mixture in the upper level (phase).
If the lower level (phase), consisting of water and
ethanol, is deep enough to reach the fuel inlet, it
could be pumped directly to the engine(s) and cause
significant problems. Engine problems can also result
from the reduced ethanol/fuel mixture left in the
upper phase of the tank.

Additives

There is no practical additive known that can prevent
or correct phase separation. The only solution is to
keep water from accumulating in the tank.
If phase separation does occur, your only remedy is
to drain the fuel, clean and dry the tank completely
and refill with a fresh, dry load of fuel.

Fuel Filters

Mercury already provides the appropriate level of
filtration to protect the engine from debris. The
addition of another in-line filter to the system may
create a possible flow restriction that can starve the
engine(s) of fuel. It is advisable to carry extra on-
190 Montauk
Example of Phase Separation
Fig. 3.5.1
4
1 CONDENSATION
UPPER PHASE (WATER+FUEL+ETHANOL)
2
3 LOWER PHASE (WATER+ETHANOL)
4 FUEL INLET TO ENGINE
CAUTION
!
The use of fuels containing ethanol higher than
10 percent (E-10) can damage your engine and/
or fuel system and will void the warranty.
E85 FUELS COULD SERIOUSLY DAMAGE YOUR
ENGINES AND MUST NEVER BE USED.
engine filters in case filter plugging from debris in
the fuel tank becomes a problem during boating.
Your Boston Whaler dealer will have recommendations
regarding filters that meet Mercury's specifications.

Maintenance

Periodically inspect for the presence of water in the
fuel tank. If any is found, all water must be removed
and the tank completely dried before refilling the tank
with any fuel containing ethanol.

Storage

Long periods of storage and/or non-use, common to
boats, create unique problems. When preparing to
store a boat for extended periods, of two months or
more, it is best to completely remove all fuel from
the tank. If it is not possible to remove the fuel,
maintaining a full tank of fuel with a fuel stabilizer
added to provide fuel stability and corrosion
protection is recommended.
• Add fuel stabilizer/treatment at
manufacturers recommended dosage.
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