Fei Bao F18-f Assembly Manual - page 9
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F E I B A O F 1 8 - f
There is also a problem with the internal tubing supplied at the factory in the tanks. After some
time in kerosene the tubing tends to get stiff and hard. We recommend changing these lines with
flexible black buna smoke tubing which remains flexible.
After getting the assembly out, remove the factory provided tubing and reinstall with the
recommended tubing, Assemble as the above right picture shows. Insert the assembly and check
that you use enough tubing to allow the clunk to touch in the bottom back corners. When
satisfied, use tie wraps or fine safety wire for security to prevent the tubing and clunk from
falling off. Gently bend the vent line to reach the top of each tank, You should also notch the
vent tube with a small file to provide for continued air flow should the tube come into contact
with the top of the tank.
Insert the stopper and clunk assembly into the tanks and tighten the screw. Do not over tighten
the screw and strip out the stopper assembly. It only needs to be tight enough to prevent leaks.
Mark a “V” over the vent line on each tank to remind you where the vent line is.
Testing tanks for leaks, attach some tubing to one of the tanks, immerse the tank into water,
and blow into the tubing to check for leaks. Do this for each tank. When satisfied there are no
leaks, put the tanks aside. Do not use a compressor or hand pump to test the tanks as too much
pressure could blow the tanks apart at the seams. Then you will have a big job to repair them
which would be to scuff, clean and glue them again with an epoxy. The next step is not required
but may be done to your liking just as an extra security seal on the tanks.
Optional Fuel Tank Reinforcement
It has been experienced on a couple of occasions were the fuel tanks have leaked. They were
caused by too much pressure during the fueling process. The concave side of the tanks, tend to
flex under this pressure and may crack the lapped glue joint. The following modification has
cured the problem. It is also sensible to be careful during the fueling procedure to slow the rate
of fuel going in as the tank becomes near full.
a) Solvent clean outside surface then use #80 grit sandpaper to scuff the surface area.