Thank You for selecting the finest American Made engine available. With simple care and common sense your engine will provide you years of trouble free service. This product does require mechanical ability and know-how to operate. You must be the judge of your own ability. YOU are the person who will control your model and engine in a safe manner and must assume all responsibility for your activity. (Read safety instructions.)

Take a few moments to familiarize yourself with the various parts of the engine as shown in the view below. The engine may not have high compression until the piston ring is seated. DO NOT DISASSEMBLE YOUR ENGINE! Doing so will void your warranty. No exceptions!

  These engines are designed for beam type mounting. Securely mount the engine an hardwood mounts or firewall mount with a good quality motor mount. Be sure mounting surface is flat and parallel and all mounting holes line up, the crankcase could become distorted if screws or mounts are forced. We strongly advise against using a soft or rubber mount installation as our engines are correctly balanced and these mounts can cause excess vibrations from resonance frequencies.

Fuel tank should be located as close to the engine as possible. The center line of the tank should be within 1/2 inch above or below the center of the carburetor.

Fuel pressure is recommended if you are unable to obtain even run throughout the whole tank of fuel. FOR TANK PRESSURE USE NIPPLE IN BACK COVER. You will have to drill this with a 1/16" diameter drill. Remove back cover before doing this.

  USE A LONG GLOW PLUG!!! USE A R/C OR IDLE BAR TYPE PLUG for R/C flying where a reliable idle is required. For FF or C/L flying use a standard long plug without idle bar for maximum performance. The heat range will be determined by many factors. Type fuel, prop size and compression ratio. Start with a medium heat range if the option is available.

You will also need a 1.5 volt battery, quality propeller (refer to prop chart below) and good commercial grade two cycle glow fuel with 5% to 15% nitro-methane (more helps in cold weather). Be sure the fuel contains the right percentage of oil (20%) and be sure the fuels oil contains at least a 50-50 mix of castor oil. Not all synthetic oil. Keep fuel clean and filter it during fueling. Keep exposure to air to a minimum as methanol will absorb moisture rapidly.

  All RJL engines are produced to the highest standards and inspected before leaving the factory, but they are not "BROKEN-IN" and will require approximately 30 minutes of running before the full potential of the engine is realized. Break-in can be accomplished by airborne or bench running.

A model engine makes sounds that will tell you how it's performing. You'll have to listen very carefully for them, recognize their message, and make adjustments to the fuel control needle valves accordingly. The mixture of fuel and air is controlled by the amount of fuel metered by the needle valve.

RICH MIXTURE running is characterized by a slower, sometimes irregular, sputtering exhaust sound. The exhaust gas will be smoky and probably contain small droplets of oil. This condition is good for Break-in since the engine receives excess lubrication and runs cooler.

SLIGHTLY RICH type setting is fast enough to pull the airplane but is still too rich to achieve full RPM's. This is the setting you normally look for before launching the airplane because the engine will run leaner when airborne.

PEAKED RUNNING is obtained as the main needle is closed (clockwise), this reduces the amount of fuel mixed with the air drawn into the engine. At a specific point, which varies with each engine, air temperature, altitude and relative humidity, the exhaust note will change into a smooth, steady note. If the needle is closed further, the note will stay smooth, but will weaken. The peak occurs just at the break point from a rich setting and further leaning will ruin the engine. A lean setting raises the engine heat above the safe point, reduces lubrication, and destroys glow plugs and piston/cylinder fit due to high combustion temperature. This is very harmful to the engine and your investment. Learn to tune the engine before flying. Remember, a little rich is always preferred for long motor life.

  Open the high speed needle valve about 4 turns. DO NOT CONNECT GLOW PLUG TO BATTERY YET. With throttle at full open setting, choke the engine by placing your finger over the carburetor/venturi inlet and slowly turn the prop over six to ten times counterclockwise. You should see fuel being drawn up the fuel line. If fuel is not drawn into the carburetor, open the main needle two more turns and unscrew the idle needle two turns and repeat the above. Don't allow engine to hydraulic lock (this means cylinder filling with fuel and piston being unable to compress it). If this occurs, remove glow plug and rotate propeller. Don't force it, serious internal damage can result. For throttle equipped engines, open the carburetor barrel about quarter-way. NOW Connect the 1.5 volt battery to the glow plug and pull the prop through until you feel a bump before compression. Now the engine will start with your electric starter. The C.15 engine has extremely high performance timing and may always require an electric starter.

Once the engine starts, open the carburetor to full throttle. At this time the engine should be running very rich. Slowly turn the main needle valve in and the engine should start speeding up. If it slows, dies or only starts with a brief bust of power and stops, the needle valve setting is too lean. Unscrew the needle 1 more turn and try again. If engine starts, runs slowly and briefly the mixture is too rich. Turn needle in 1/2 turn and restart. IF THE ENGINE DOES NOT FIRE AT ALL, refer to the troubleshooting section in this manual.

  RJL Conquest engines are fitted with a variable mixture carburetor which automatically alters both fuel and air mixtures as it's closed. Best and most reliable carburetor settings are obtained after engine break-in.

1> Start the engine and open the carburetor to the full open position, then adjust for peak R.P.M. with the main needle as previously described.

2> Close the carburetor barrel slowly until the lowest possible speed is reached without the engine stopping.

3> Go to full throttle after about 10 seconds of idling. If the engine gains speed slowly, the idle mixture is too rich. If the engine stops, the idle mixture is too lean. Turn the idle mixture disc (located behind the main needle with + & - marks) clockwise if mixture is too rich and counterclockwise if too lean. Very slight movement is required.

The engine will accelerate from idle to full throttle smoothly and instantaneously when properly adjusted. The engine may not idle well at a low setting until it is broken in.

AIRBORNE BREAK-IN (also see "aircraft installation")
  1> BREAK-IN running should be done with the recommended propeller (see chart) at a slightly rich setting. The needle valve should be set at a point just into this range from a rich setting. For throttle equipped models, fly the plane at maximum throttle for 2 minutes, then throttle back for approximately 30 seconds. Repeat this sequence until approximately 20 minutes of accumulated running time has been obtained. For FF & C/C models, set needle richer than described above. Additionally, certain maneuvers, such as "CUBAN EIGHT'S", that allow the engine to load and unload are recommended. AVOID PROLONGED CLIMBING MANEUVERS AT MAXIMUM THROTTLE.

2> After the first 20 minutes change to normal size prop and fly an additional 20 minutes. Continue to run the engine at a slightly rich setting and fly your normal pattern.

3> After the above break-in period, run the engine at a normal peak needle valve setting. This should be a little on the rich side because engines run leaner in the air. Higher nitro may be used.


The initial bench break-in period is also approximately 40 minutes (20 minutes bench and 20 minutes airborne). During this time, run the engine at a rich setting. It is best to run the engine for about 3 minutes, then allow it to cool. The heating and cooling aid break-in.

1> Start the engine and run it at a rich full throttle for about 1 minute, if carburetor equipped, then let it fast idle (about 4000 rpm's) for 30 seconds. Repeat this sequence for about 10 minutes of running time.

2> Increase the full open throttle time to about 2 minutes followed by a 30 second idling period (about 3,500 rpm's). Do this for an additional for 10 minutes.

3> Install the engine in your aircraft. Using an normal size prop, proceed as described in step 2 of "AIRBORNE BREAK-IN".

  Generally most engine starting problems can be traced to bad glow plugs, weak starting batteries, or inadequate fuel systems.

  The glow plug when connected to a 1.5 volt battery should glow a bright orange. If the plug slightly glows the battery or plug should be replaced.

If the seal leaks around the center plug post, replace it.

The glow plug element should be examined after several flights. If the element is deformed or touching the side of the plug body, replace it. If the glow plug element is pitted or has a frosty look, the engine is running too lean or plug is too hot of heat range and continued running will seriously harm the engine.

  The most frequent problems encountered with fuel systems are:

1> Improper fuel tank location. The center line of the fuel tank should be located on the center line of the carburetor.

2> Fuel pick up in tank is not free.

3> Dirt or contaminates in the fuel, tank, lines, filter or carburetor.

4> Holes in the fuel line. The tear resistance of silicon tubing is very low and it's not uncommon to develop a hole where the fuel line is assembled over the edges of brass tubing. If the engine runs well on the first half of tank and then quits, it's almost always caused by a hole in the pick up line inside the tank. Look for bubbles in the fuel line, this is also a sign of holes.

  When you finish flying for the day, run your engine dry by removing the fuel line at a moderate speed or allow the fuel tank to run dry. Running the engine dry removes any methanol residue from the internal engine components. This methanol attracts moisture and will result in rust and corrosion if this procedure is not followed. It is best to squirt some RJL AFTER RUN OIL in the carburetor, then flip the propeller about 10 to 20 times. This oil will keep castor based fuels from gumming and protect internal engine parts from rust and corrosion. When storing your model between flying sessions, it is best to wrap your engine in a rag or plastic to prevent dust, dirt and moisture from entering the engine. The engine should also be wrapped in a rag at the flying field between flights.

If dirt does enter the engine do not turn it over until it has been flushed out completely. Alcohol is recommended for this. DO NOT USE carburetor cleaner or chlorinated industrial solvents as they may attack the plastic parts of the engine. The following steps may be used as a disassembly/assemble guide: (see warranty)

1> Remove carburetor, exhaust system/muffler and glow plug.

2>Remove the rear cover.

3>Flush engine out completely using alcohol or mild solvent.

4>Install rear cover.

5> Install carburetor, glow plug and exhaust system.

To disassembly/assemble further (doing so will void warranty however):

6> Remove items indicated above.

7> Remove 4 head screws and lift cylinder/piston/rod off lower crankcase.

8> Slide crankshaft out rear of crankcase.

9> Ball bearings are press fitted into the crankcase and require heating of the crankcase and special tools to remove.

10> Clean all crankcase gasket surfaces with cleaning solvent. Do not use a knife or sharp edged tool or sand paper. Be sure rear cover O-ring is in perfect condition. A leaking rear cover can cause a variety of irregular running conditions.

11>Reassemble parts by reversing these directions.