Improving and Replacing the Fuel Filler
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I had a
lot of trouble with water and dirt in my fuel. My fuel filters clogged often, sometimes
twice in one day, especially when motoring in a chop. I always found water in the clear bowl of my
filter, so last spring I drained the tank dry. I found about a quart of water
in the bottom, along with a lot of black gooey stuff. Of course this black
muck consisted of dead microbes, which live in the interface between the
water and fuel (oil) layers. One of
the keys to keeping this muck out of your tank is to keep the tank free of
water. On the Scanmars, this is especially difficult due to the
location of the fuel fill. It is on the starboard side, very close to the
edge of the deck and toerail. This means that when
water gets on the deck, the fuel deck plate is often at least partially under
water. The gaskets
on these deck plates is not the greatest, and even worse is the poor
method of locking the cap into the neck of the fitting. The threads on the
cap are easily stripped, as it is plastic and has a very coarse, interrupted
thread. When I inspected mine, it
became obvious that the fuel fill sitting on the deck was a major source of
water intruding into the fuel tank. I
decided to attack this problem in two ways. One was to replace the fuel fill
deck plate. This is not as easy as it seems, as the Scanmar
uses a 2” fitting; 1½”
is the standard size.
This means that the fuel fill hose itself is 2”. I believe that Scanmar did this because commercial docks often have a
large nozzle on their fuel pumps; this allows the Scanmars
to refuel from commercial fishing docks. Vetus den Ouden of |
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The new
deck plate is made of cast stainless steel, weighs about 2 pounds, and is
built like a brick outhouse. The cap
is stainless steel, not plastic, the threads are robust, and there is a
substantial O-ring under the cap. The
original deck plate on the Scanmar was thin stamped
stainless steel. However, the chain which holds the cap to the neck is mild
steel, which of course quickly rusts away. |
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The
second part of keeping water out of the fuel tank was to raise the deck plate
so that it was not underwater when the deck has a little water on it. Copying
an idea I saw on another cruising boat, I decided to make a thick
doughnut-shaped bezel on which to mount the deck plate. This would raise the
cap of the deck plate off the deck by ½”. Here’s
a recap of how I accomplished this. |
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The old
fuel deck plate was removed. Getting the huge 2” hose of the neck of the fuel
deck plate was a real chore. It is handy to have a thin, small and wiry crewmember
with the upper body strength of Godzilla in order to yank it off. This person has to go into the cockpit
locker to reach this hose. Well, I
didn’t have such a crewman, so I had to hire someone just to get the hose
off. Here the old deck plate has been removed, and the edges of the balsa
deck core are exposed. I cleaned all
with acetone. |
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One of
the original screw holes was so close to the edge of the filler opening, it
broke through and so was holding nothing.
I removed the balsa core from the old screw holes using a heavy wire
(coat hanger bent in a shallow “L”) and also from the inside edge of the
opening. I had found that some water had gotten through the caulking, as
one area of the balsa was a bit soggy, Thickened
epoxy was applied to the scooped-out edges of the opening, and injected into
the old screw holes using a plastic disposable syringe. Now I
was sure that no water could get into the deck core here! |
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To make
the “washer” or bezel, I bought a 12” x 12” square of sheet fiberglass from
the industrial supplier McMaster-Carr.
This is specially formulated structural fiberglass made from many layers of
cloth impregnated with resin, and compressed into a perfect sheet of ½”
thickness. It is as strong as hell, and will not rot. Of course, if you happen to have some scrap
fiberglass laying around, that will work too.
Another alternative would be to use plywood that you have completely coated
with epoxy, but I think the fiberglass is the safest and neatest method. Using a
hole saw, I first partially cut a hole for the neck; using the center ¼”
drill hole created by the hole saw’s central drill bit as a guide, I used a
larger hole saw (4¼” I believe) to completely cut through the outer,
concentric hole in the sheet. This gave me a 4 ¼” disk of fiberglass with a
¼” drill hole in the center. Using the smaller hole
saw, I completed the cut out the hole for the filler neck. I beveled the edge
of the doughnut using a pad sander to decrease toe-stubbing, and predrilled
the holes to fit the 3 screws. I
sprayed it all with dark green Rust-Oleum paint, to
denote diesel fuel. |
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I laid the
new deck plate on the fiberglass “washer”, placed the assembly in position on
the deck, and drilled new holes for the screws. I redrilled these
holes with a much larger drill bit than needed, and filled the holes with
thickened epoxy. Once this dried, I drilled new holes of the correct size for
the screws into the plugs of epoxy. This ensures that even if water made its
way under the screw heads, it cannot reach the balsa core. Every hole I drill
into the cored deck or hull I prepare using this same method: drill oversized
holes, fill with thickened epoxy, let dry and re-drill with a smaller drill. |
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I gooped on plenty of caulking, Life-Caulk, on the
underside of the washer and deck plate, and screwed it all down.
Unfortunately, I mistakenly bought brown caulk instead of white, but
otherwise it came out pretty fair. Here’s
the finished product. Muscling the fill hose on to
the barb of the deck plate was another hassle; once again, I hired our local
fiberglass guy, Joel, to put the hose back in place. Joel is a compactly-built
ex-Marine and has arms like a fiddler crab.
Even he had a lot of trouble forcing the hose on. Now
when the deck gets wet, the fuel fill is safe from water leakage! |
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