We've used and can recommend the Du-Bro #334 Kwik-Fill Fuel-
ing Valve (not supplied). The fueling valve is installed in the main
fuel feed line, between the tank and the carburetor. You fill and
de-fuel the airplane through the valve. Specific instructions will
come with the valve. Mount the fueling valve on the firewall, just
under the surface of the cowling, using a SIG #SIGSH759 Fueling
Valve Bracket (not supplied). Make a 5/16” dia. hole in the cowl-
ing, directly over the fuel valve, to allow the fueling probe to be in-
serted into the valve.
Method 2
You can use 3-line plumbing inside your tank to provide a dedi-
cated 3rd line for filling and de-fueling. The 3rd line is bent down
to just reach (but not touch) the bottom front of the tank. This is
the line that you will hook up to your fuel pump to fill and empty
the tank. This line must be capped after filling to keep the fuel
from siphoning back out of the tank. You can cap it with a simple
bolt of the correct size, or with an after market "fuel dot".
Note in the photos that the correct orientation of the fuel tank body
in the airplane is with its neck towards the top of the tank.
TANK ASSEMBLY
❑
1) Inside the tank is a piece of flexible fuel line tubing. Reach
inside the tank with a tweezers or needle nose pliers to get a hold
of the fuel line tubing and pull it out. CAUTION: Don't squeeze
too hard and put a hole in the tubing! Now shake the tank a few
times to make sure there is no dirt or plastic shavings inside!
❑
2) Take a close look at the rubber stopper. Notice that it has
two open holes and one closed one.
a) Assemble the front metal clamp, the rubber stopper, and the
rear metal clamp with the bolt. Screw the bolt in, from the front,
just enough to hold the front and rear clamps loosely against the
rubber stopper. Do not tighten the bolt at this point. Rotate the
front and rear metal clamps until their holes line up with the two
open holes in the rubber stopper. You should be able to see day-
light completely through the two holes.
b) Using the two shortest of the three supplied aluminum
tubes, carefully poke the tubes through the two open holes in the
stopper assembly. Keep pushing the tubes in until 3/8" of tube
sticks out in front of the stopper assembly.
Note: If you are planning a 3-line tank system, you will be using
all three of the holes. Use a sharp hobby knife blade to pierce the
front wall of the closed hole. Install the 3rd tube in that hole, again
with 3/8" of tube sticking out in front of the stopper assembly.
❑
3) Put the plain end of a #47 drill bit about 1/4" inside the back
end of the vent tube. Using the drill bit for leverage, slowly bend
the back end of the vent tube upwards at least 45
O
. Do not to put
a kink in the aluminum tube.
❑
4) Test fit the completed stopper assembly into the neck of the
fuel tank. Hold the tank up to a strong light and look inside to see
if the vent tube is close to the top of the tank. If not, take the stop-
per back out of the tank and adjust the bend in the vent tube as
needed. The metal tube should not touch the tank, or vibration
may cause it to wear a hole in the plastic tank over time.
❑
5) Take the stopper back out of the tank. Slide the piece of sil-
icone tubing that came with the tank onto the inside end of the
aluminum feed tube. Then add the metal clunk pickup to the other
end of the silicone tubing. Test fit the stopper back in the tank to
make sure the clunk can swing freely without hitting the back of
the tank. If it hits the back end of the tank, shorten the silicone
tubing in a small amount at a time until the clunk can swing freely
inside the tank.
Note: If you are using a 3rd line for filling the tank, repeat steps 3
and 4 to bend the fill tube towards the bottom of the tank. Make
sure it does not actually touch the bottom of the tank.
❑
6) When everything is right, tighten the screw in the stopper
cap until the cap is snug in the neck of the tank. Then test the
fuel tank for leaks! Fill your kitchen sink with water. Slip a piece
of fuel line tubing onto the tank vent tube. Submerge the tank in
the water, holding your thumb firmly over the fuel feed tube. Blow
air into the other end of the fuel tubing and watch for air bubbles
coming around the cap of the tank. If it's leaking, tighten the screw
in the cap a little at a time until the leaking stops.
❑
7) Trial fit the tank in place inside the fuselage to familiarize
yourself with how it mounts. The front of the tank should fit
through the hole in the firewall. The main body of the tank is sup-
ported by the contoured hole in the fuselage former. Note: If your
engine mounting bolts are protruding behind the firewall, it's a
good idea to take them out and shorten them so they don't pro-
trude. If they contact the tank, they might dig into the tank and
cause a leak in the future. Cut them off or use shorter bolts.
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