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are two exceptions to this approach:
One, fuel fill fittings may be smooth
rather than barbed, and two, fuel fill
hoses are required to use two clamps
rather than one.
I often encounter a seemingly
maniacal approach by installers toward
double hose clamp use, installing twin
clamps where the second one does
little good and may damage the hose
in the process. If only one clamp will
bear on a fuel distribution fitting, use
just one high-quality clamp. In fact,
only the highest quality clamps should
be used throughout the fuel system.
A final note on the use of pipe-to-hose adapters—some are designed
to be used without clamps, such as
Parker’s Push-Lok series. These fittings
are characterized by a yellow plastic
collar, and they must be used only
with Push-Lok series hose, and Push-Lok hose is not available in a Type
A- 1 series. Therefore, these fittings
should not be used with ordinary hose
or in fuel plumbing systems.
Armored hose falls into an entirely
different termination category. Instead
of barbed pipe-to-hose adapters and
hose clamps, it uses either swaged or
field-assembled sleeve and threaded
insert terminals. The latter can be
installed by boatbuilders, yards and
experienced do-it-yourselfers, while
the former requires the use of a
swaging machine.
Installed properly, either works
very well. The terminals themselves
are available in plated steel, brass or
stainless steel, the prices for these
going up appreciably for each one.
Armored hose is also significantly
more expensive than conventional
fuel hose. Plated steel fittings from
the original equipment manufacturer
(avoid using aftermarket fittings
from those other than the hose
manufacturer) offer relatively good
corrosion resistance; however, they
should also be coated with a corrosion
inhibitor.
If maximum corrosion resistance is
desired, then use the brass or stainless
steel fittings. My preference is for
brass, except on aluminum vessels.
There is one important
requirement for the field-attachable
terminal, and it relates to the story I
shared at the beginning of this column.
While assembly is straightforward
enough, the instructions for attaching
these terminals offer the following
warning: “Caution: Do not attempt
to assemble these fittings to the
hose without using a mandrel.”
The mandrel, in this case a type of
spindle, is available in kit form for a
range of hose sizes and ensures that
the terminal does not damage the
hose during installation.
If the assembly mandrel isn’t used,
a flap is often formed, which acts like
a check valve andcan prevent fuel
from flowing. The flap often falls into
place only after the hose has been
filled with fuel for several months or
even years. In the aforementioned
case, the vessel was just over a year
old, the flaps formed and fuel ceased to
flow. It took hours of troubleshooting
and several more hours to replace the
affected hose ends before the engine
would run normally again.
Regardless of whether you use the
standard A- 1 black rubber hose or
the armored variety, the attention to
detail with which the installation is
carried out drives the system’s, and
ultimately, the vessel’s reliability.
Some fuel distribution pipe-to-hose
adapters simply can’t support two
clamps. In that case only one clamp should
be used.; Terminals used with armored
hose. While costly, it results in a very
durable and long-lived installation.
When the required tools aren’t used for
assembly of armored hose, a fuel starving
flap can be formed.