Passagemaker Magazine

Gearhead

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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.