User Manual

❑ Fuel Recommendation
Fuel can make a big difference in the way your engine performs. We rec-
ommend using two types of fuel with the XL .61RFS. For the break-in
period you must use a fuel containing no more than 10% nitromethane and
no less than 20% Castor Oil lubricant. Use of fuel containing more than
the recommended percentage of nitromethane or any synthetic lubricants
will cause the engine to run too hot and result in excessive wear and engine
failure in a very short period of time. Once the engine has been adequately
broken in (about 1 gallon of the recommended break-in fuel), a fuel con-
taining up to, but no more than 15% nitromethane and no less than 16%
Castor Oil and synthetic lubricant blended fuel can be used.
Note: We do not recommend using fuels that contain only synthetic
lubricants. Synthetic lubricants have a much lower flash point than Cas-
tor Oil lubricants. Flash point is the point at which the lubricant begins to
actually burn and loses its lubricating qualities. Using fuels containing a
blend of Castor Oil and synthetic lubricants results in an engine that runs
cooler and lasts longer. One lean run using a fuel containing only syn-
thetic lubricants can cause engine failure. Using fuels with a Castor Oil
and synthetic blend of lubricants greatly reduces this chance.
❑ High Speed Needle Valve
The high speed needle valve is used to meter the air/fuel mixture at full
throttle. Turn the needle clockwise to lean the mixture or turn the needle
counterclockwise to richen the mixture. When you start the engine for the
very first time the needle valve should be turned in completely, then backed
out 2-1/2 turns. When you start the engine after that, leave the needle
valve in the same position it was in when you shut down the engine.
❑ Low Speed Needle Valve
The low speed needle valve meters the air/fuel mixture at idle and during
transition from idle to full throttle. Turn the low speed needle clockwise to
lean the mixture. Turn it counterclockwise to richen the mixture. The low
speed needle valve is preset from the factory, but minor adjustments may
need to be made to suit your application (i.e., fuel used, glow plug and
environment all contribute to the setting). To reset the low speed needle
valve to the factory setting open the carburetor barrel completely. While
holding the barrel open, turn the needle in until it stops. From this point, turn
the needle out 2 complete turns. This is the factory setting. It is possible to
turn the idle mixture so lean that the engine will not draw fuel.
Note: The XL .61RFS engine is a ringed engine. A ringed engine is
designed differently from a typical ABC designed engine that you might be
more familiar with; therefore, you will not feel much hesitation as the pis-
ton moves through the top of the stroke. A ringed engine does not have any
taper in the sleeve. Ring tension is what seals the combustion chamber.
When the engine is brand new, it will not feel like it has much compression.
This is because the ring has not yet been seated with the sleeve. After the
engine has been broken-in, compression will increase. The break-in proce-
dure will guide you through the steps necessary to properly break in your
new XL .61RFS ringed engine. Please follow the steps closely.
The break-in process allows the engine parts to perfectly fit to each
other and properly protect each part from premature wear. The engine
should be broken in using a fuel that contains no more than 10% ni-
tromethane and no less than 20% Castor Oil lubricant. Synthetic lubricant
fuels should not be used during the break-in procedure. For the break-in
procedure we recommend mounting the engine into the airplane it will be
used in. This way the muffler, fuel tank and throttle linkage can all be
tested in combination with the engine. If your airplane uses a cowling, it
should be removed during the break-in procedure.
❑ 1) Turn the high speed needle valve out 2-1/2 turns from the fully
closed position.
❑ 2) If you are using an electric starter to start the engine, follow the
corresponding procedure in the previous section. If you are starting the
engine by hand, follow the appropriate procedure in the previous section.
❑ 3) Open the throttle barrel to approximately 1/4 throttle. Connect
the power to the glow plug. Start the engine using an electric starter or by
hand. If starting by hand you will need to vigorously flip the propeller
through the compression stroke several times before the engine will start.
❑ 4) Once the engine starts open the throttle barrel to about 1/2 throttle.
You may need to lean the high speed needle valve in about 1/4 turn to keep
the engine running at half throttle.
HIGH & LOW SPEED NEEDLE VALVES
BREAK-IN PROCEDURE
Ideally you want to use a propeller that the engine will turn in the 9,000 -
12,000 R.P.M. range on the ground, yet power the airplane sufficiently.
Using a propeller that is too small will cause the engine to run at too high
an R.P.M. Using a propeller that is too large will cause the engine to run at
too low an R.P.M., causing the engine to lug down too much. In both
instances this will lead to difficulty in making needle valve adjustments,
premature engine wear and eventual engine failure.
Acceptable Propellers
The XL .61RFS can be started using an electric starter or it can be started
by hand. For safety and ease of starting, especially when the engine is
brand new, we recommend using an electric starter. The following two
procedures should be done with the power to the glow plug off.
STARTING PROCEDURE
❑ Starting by Hand
When starting the engine by hand always use a chicken stick. If you must
use your finger, wear a good leather glove to prevent the propeller from
cutting you. Never use your bare hand or serious injury could result. To
make the engine easier to start by hand it should first be primed. This is
done by opening the carburetor completely and choking the engine by put-
ting your finger over the muffler opening. With your finger over the muf-
fler opening, “pull” the propeller through the compression stroke 2 - 3
times. This will draw fuel into the engine. Over-priming the engine can
cause the engine to “hydro-lock” or flood. This is a result of too much
fuel in the engine before it actually fires. Remove your finger from over
the muffler opening and “pull” the propeller through the compression
stroke once to check for a hydro-locked condition. Never try to start the
engine if it is in a hydro-locked state. This could cause serious damage
both to yourself and to the engine.
❑ Starting with an Electric Starter
When using an electric starter it is not necessary to prime the engine. The
starter turns the engine over fast enough that the engine draws fuel on its
own. Priming the engine prior to using an electric starter can cause the
engine to “hydro-lock” or flood. This is a result of too much fuel in the
engine before it actually fires. Trying to start the engine with an electric
starter while the engine is flooded can cause extreme damage to the engine
and/or cause your propeller assembly to come loose. “Pull” the propeller
through the compression stroke one time by hand to check for a hydro-
locked state before applying the starter.
Note: If the engine becomes hydro-locked, do not force the propeller
through the compression stroke. Remove the glow plug and quickly flip the
propeller, or apply an electric starter, to expel the fuel from the cylinder.
11 x 8 11 x 9 11 x 10
12 x 6 12 x 7 12 x 8
13 x 5 13 x 6 13 x 7
Use a 12 x 6 propeller for the break-in procedure