WARNING

PLEASE READ ALL SAFETY INSTRUCTIONS! Failure to read, understand and follow these instructions could result in personal injury and/or property damage to yourself or others.

Take a few moments to familiarize yourself with the various parts of the engine. DO NOT DISASSEMBLE YOUR ENGINE! Doing so will void your warranty. No exceptions!

STARTING AND BREAK-IN

All K&B engines are produced to the highest standards and inspected before leaving the factory, but they are not “BROKEN-IN” and will require approximately 60 minutes 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 smokey and probably contain small droplets of oil. This condition is good for Break-in since the engine receives excess lubrication and runs cooler.

FOUR CYCLING is a rich type setting, but it is fast enough to pull the airplane. This is the setting you normally look for before launching the airplane because the engine will run leaner when airborne.

PEAKED OR TWO CYCLE. As the main needle is closed (clockwise), it 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 quickly into a smooth, powerful 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 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.

BREAK-IN FORMULA: 22% Degummed castor oil, 5 to 10% nitro-methane, and the balance methanol.

AFTER BREAK-IN: The nitro-methane percentage may be increased to 15% if desired. LOW QUALITY FUELS CAN RUIN THE ENGINE IN A SHORT PERIOD OF TIME. Never use fuel with less than 18% oil content by volume.

PROPELLER SIZES

Note engine shaft size 1/4"x28. Be sure prop is balanced.

 

Break-in	12x7
Normal Models	12x8 13x6

          

CARBURETOR SET UP

WITHOUT battery connected, open the carburetor barrel to wide open position. Open the high speed needle valve as described above. Choke the engine by placing your finger over the carburetor air inlet and slowly turn the prop over three times counter clockwise. You should see fuel being drawn up the fuel line. If fuel is not drawn into the carburetor, open the main needle one more turn, and be sure the idle mixture disc notch is in the upright position, then repeat the above. Fuel should be drawn into carburetor.

Close the barrel to about the 1/3 open position and connect the 1.5 volt battery to the glow plug, start the engine with your chicken stick or 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 the main needle in 1/2 turn and restart. IF THE ENGINE DOES NOT FIRE AT ALL, refer to the TROUBLE SHOOTING section in this text.

Now adjust the main needle as described in STARTING AND BREAK IN above.

ADJUSTING THE R/C CARBURETOR

K&B 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 disc clockwise if mixture is too rich and counterclockwise if too lean.

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 or accelerate as quickly until it is well broken in.

1.    BREAK-IN running should be done with the recommended propeller at a slightly rich setting. The needle valve should be set at a point just into this range from a four cycle setting. Fly the plane at maximum throttle for 2 minutes, then throttle back for approximately 30 seconds. Repeat this sequence until approximately 45 minutes of accumulated running time has been obtained. 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 45 minutes change to normal size prop and fly an additional 45 minutes. Continue to run the engine at a slightly rich four cycle 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. 5% - 15% nitro may be used.

NOTE THAT THE ENGINE MUST BE FIRMLY MOUNTED ON A SOLID TEST STAND. DO NOT CLAMP ENGINE IN A VISE. Muffler may be used during bench break-in.

The initial bench break-in period is also approximately 90 minutes (20 to 30 minutes bench and 60 minutes airborne). During this time, use the recommended break-in propeller and run the engine at a rich setting. It is best to run the engine for about 10 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 1-1/2 minutes, then let it fast idle (about 3500 rpm’s) for 30 seconds. Repeat this sequence for about 20 minutes of running time.

2.    Increase the full open throttle time to about 3 minutes followed by a 30 second idling period. Do this for an additional for 20 minutes.

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

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. Do not use a back cover mounting plate as the screw bosses are not designed to take engine torque.

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. See illustration.

Muffler pressure is recommended as it provides an even run throughout the whole tank of fuel.

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

GLOW PLUGS: 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 and continued running will seriously harm the engine.

FUEL SYSTEMS: The most frequent problems encountered with fuel systems are:

1.    Improper fuel tank location. The center line of the carburetor should be located on the center line of the fuel tank.
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 are finished 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. It is best to squirt some K&B 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:

1.    Remove carburetor, muffler and glow plug.
2.    Remove the back cover and head.
3.    Flush engine out completely using alcohol or mild solvent.
4.    Install back cover and head.
5.    Install the glow plug and carburetor.

SCREW ON HEAD: The screw on head on your new 61 ABC engine has been torqued to 26 foot pounds at the factory. After you have run 2 to 3 gallons of fuel through the engine, check the head for tightness with the spanner wrench supplied. Check the head immediately after a flight so the engine will be at running temperature. Support your engine by firmly holding the prop and front of the engine so as to not break engine mount loose from the fire wall. NOTE: The head is installed at the factory with anti-seize compound. Before reinstalling head, make sure threads are clean and reapply anti-seize compound for aluminum (available at auto parts stores) to threads.