‘The engine just stopped, we’re anchored now, I changed the primary and secondary fuel filters, they were clean but I changed them anyway, the ngine cranks but it just won’t start, what should I do?” These, the opening
lines of an email I received from a client as he was cruising
the Intracoastal Waterway, are the genesis of a tangled
troubleshooting tale that marries good intentions with
The hose used to supply, transfer and return fuel to and
between tanks and engines must be durable and rated for
the application. While there are many types of fuel hose
ratings, one is especially important: its flame resistance.
With a few exceptions, to be compliant with American Boat
& Yacht Council (ABYC) Standards, hose used for supply,
return and transfer should carry an A1 designation (this
includes A1-15, which has enhanced permeation resistance
for gasoline). Hose that carries this designation is capable
of withstanding exposure to flame for a minimum of two
and one-half minutes without rupturing and thereby not
feeding the fire.
Hose used for fuel fill between the deck fitting and
the tank should carry an A2 designation. It, too, is flame
resistant, however its permeation resistance is lower than
A1 and therefore its use where it remains filled with fuel
for extended periods should be avoided.
In addition to these markings, fuel hose that meets
ABYC Standards must also be clearly
and permanently marked with
the hose manufacturer’s name or
trademark, the year of manufacture
and the flame resistance designation.
The type must also be in block capital
letters at least every 12 inches, and
each letter must be a minimum of
⅛-inch tall. When I encounter fuel
hose that carries markings other
than these, or hose that is unmarked
entirely, I simply can’t be certain it
will perform properly in both day-to-day use and in the event of a fire.
Another common fuel hose
designation is B series, which
includes B1 and B2. Type B hose
is designed primarily for outboard
motors; it carries no flame resistance
rating whatsoever. This type should
not be used for inboard applications
and where flame resistance and
ABYC compliance are desired.
While there are many different
manufacturers of fuel hose, there are primarily two types of
the A1 series: conventional black rubber and armored hose.
The former is used extensively by boatbuilders and repair
yards, and when supplied by reputable manufacturers and
properly installed, it can be expected to provide reliable
service for at least 10 years.
Armored hose, on the other hand, is designed for the
toughest applications. It is virtually indestructible and can
be expected to outlive conventional hose by a factor of two
to one. It uses a tough braided-steel jacket, which itself is
protected by an outer layer of rubber-like material, and it
must be used with proprietary terminals or ends. These
two factors make this the Cadillac of hose; however, it’s
not without its shortcomings.
A fuel hose’s integrity is only as good as the manner in
which it’s terminated; if it’s not carried out correctly
leaks will happen. Traditionally, fuel and many other
hose applications rely on the tried and true pipe-to-hose
adapter and hose clamps. This method, if done correctly
and in compliance with ABYC Standards, is very reliable
and the cost of materials is reasonable.
The hose is slipped over a barbed, beaded or serrated
adapter (never over helical threads), and then a hose
clamp is installed. Only one is required, however, two
may be used provided both bear on the fitting. Installing
hose over smooth pipe or tubing is unacceptable. There
A2 series hose is designed for fuel fill applications. Its permeation resistance is less
than that of A1.
The Devil Is in the Details for Fuel Hose Installations
Gearhead BY STEVE D’ANTONIO
FoR MoRE Abou T FuEL HoSE TERMINATIoN
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