20
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2. The hole in the fi rewall for fuel cut wire must be
counter-bored
so the loop can travel far enough to pinch
the fuel line without overdriving the servo. The easiest
way to cut a precise counter-bore is with a 1/4" K&S brass
tube sharpened on the end. Mark a line on the tube 3/8"
[10mm] from the end and use a drill to turn the tube into
the fi rewall up to the line. This will provide a counter bore
that’s approximately 3/16" [5mm] deep.
Refer to this photo for the following three steps.
❏
3. Remove the engine mount from the fi rewall. Use a
hobby knife and/or a small, fl at-blade screwdriver to pick
the material out of the counter bore. Use your covering
iron to make sure the covering is thoroughly sealed to the
fi rewall around the hole.
❏
4. Cut the 1/8" [3.2mm] guide tube for the fuel cut wire
to a length of 11" [280mm]. Roughen the tube so glue will
adhere, then insert the tube into the fi rewall so the end of
the tube aligns with the bottom of the counter bore hole.
Use thin CA to glue the tube into the hole from the back-
side of the fi rewall.
❏
5. Using care not to get any glue inside the tube,
fuelproof the bare wood inside the hole with CA or epoxy.
❏
6. Install one of the 6-32 x 5/8" [16mm] SHCS into the
hole in the back plate mount near the engine exhaust,
then mount the back plate mount to your engine.
❏
7. Mount the engine to the fi rewall with four 6-32 x 5/8"
[16mm] SHCS and threadlocker.
