Step 1B.
4. The carburetor is correctly positioned when the throttle arm is
located on the right side of the engine when viewed from the
rear. Please note the carburetor can be rotated 180 degrees for
those applications that require the needle valve to be on the
opposite side. Tighten securely with the appropriate wrench
while applying slight pressure on the carburetor to compress the
O-ring. This will create a good, airtight seal. CAUTION: Do not
overtighten, as doing so will damage the carburetor body.
Step 2.
Break-In Procedures
Prior to starting your new MDS ringed or ABC engine, it’s
important that you first understand the break-in procedure for
your type of engine. Most modelers prefer to do this while the
engine is installed in the aircraft or heli. With today’s tolerances
and available metallurgy, the break-in time has been shortened to
the point that bench running is not necessary. If you’re not sure
whether your engine is ringed or ABC, simply look through the
exhaust port and move the piston until you can see the top
portion. If it’s ringed, you will see a dark metal ring approximately
1/8” from the top. If it’s ABC, the piston will be one piece and all
the same color of the piston.
Ringed Engine Break-In
Excessive heat build up during the first few runs can damage the
ring and cylinder. A very rich needle setting is required to keep the
engine cool while the ring seats. To set a “rich” mixture, lean the
high-speed needle for a good 2-cycle, then richen the high-speed
needle counter clockwise a full turn. While running rich, the
engine will create quite a bit of smoke and the exhaust will be very
oily. After a couple of tank fulls at a rich needle setting, you can
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MDS instruction manual 5x6.5 4/28/00 3:09 PM Page 5
