Gasoline Engine Installation; Mount The Engine - GREAT PLANES Waco YMF-5 Instruction Manual

GASOLINE ENGINE INSTALLATION

This section will cover the installation of a DL Engines DLE-
30cc gasoline engine. Other similarly sized gas engines can
be used, but be careful to space the ignition equipment as
far away as possible from the radio equipment. If you are
installing a different engine, please respect the firewall
to prop washer dimension of 6-11/16" [170mm]. Plywood
spacers are included for the DLE-30 engine. This engine is
best mounted with the cylinder inverted.
Note on the side carb DLE-30: This is supplied with 30mm
spacers and M5 metric bolts. Because of the required standoffs,
you will need to purchase longer hardware. You may use M5
bolts or 10-32 bolts and matching blind nuts. You can find these
at some larger hardware stores or fastener suppliers.
Note on the rear carb DLE-30: This is supplied with 60mm
spacers that are threaded on both ends for 5mm metric
bolts. Four M5 metric bolts are supplied with the engine.
You will need to purchase four additional M5 metric bolts,
washers, and lock washers to install the engine. Do not
attempt to use 10-32 hardware. 10-32 bolts may seem to
thread into the aluminum standoffs, but the thread fit is very
loose. Tightening #10 bolts into the standoffs will cause the
thread in the aluminum to strip and may cause your engine
to separate from the firewall.

Mount the Engine

❏
1. To install the DLE-30 gas engine, drill at the four
engraved "X" marks on the firewall first using a 1/8" [3.2mm]
drill and then stepping up to a 1/4" [6.4mm] drill if you are
using the side carb engine, or a 3/16" [4.8mm] drill if you are
using the rear carb engine. If you plan on using a different
engine, please use the vertical and horizontal centerline
"crosshair" marks on the firewall to line up the template that
came with your engine.
❏
2. If you are using the side carb DLE-30, install four 10-
32 blind nuts on the firewall from the back side. Use four
10-32 x 1" [25.4mm] bolts with four #10 flat washers to help
draw the blind nuts into the holes.
❏
3. Identify the DLE-30 engine spacers by matching the
bolt holes on the spacers to the bolt holes on the back of the
engine. For the DLE-30 side carb installation, you will need
to use thirteen of these 3mm ply spacers. For the DLE-30
rear carb, you will need to use three ply spacers. This will
set the drive washer of the engine at 6-11/16" [170mm] from
the firewall.
❏
4. Test fit the engine with the spacers and standoffs using
four 10-32 x 4" [102mm] bolts and four #10 lock washers
(not supplied). If you are using the rear carb engine, use four
M5 x 25mm bolts, four 5mm lock washers, and four 5mm flat
washers. Mark the fiberglass sub-cowl areas that you will
need to trim to clear the muffler and the cylinder head using
a felt tip pen. Remove the engine and trim the sub-cowl. Trim
additional cooling air vents in the sub-cowl to allow more
airflow across the cylinder. Note: Because of the position of
the muffler, you will need to trim away one blind nut from the
sub-cowl.
❏
5. Mix up some 30-minute epoxy and thin it down with a
little denatured alcohol. Glue the ply spacers together and
coat them with the epoxy to fuelproof them.
❏
6. Mount the engine to the firewall using a drop of thread
locking compound on the screw threads. Note: Because of
the added vibration of a gas engine, you may want to go back
and tighten these after a few flights. Check them periodically.
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