After the engine break-in you may use synthetic oils (high quality only[), also for the oil sump, instead of castor oil in order to achieve a good mixture. Before stopping the engine you should run it at full throttle for at least a minute in order to prevent damage from corrosion inside the FK 50.

After a total running time of 5 to 6 tanks of fuel has been accumulated, you can gradually set the carburetor for maximum Rpm. Slowly turn the needle valve to the right. Before setting the idle speed, mount the propeller that is intended for later use. Various aspects influence the choice of propeller size: the size of the airplane, wing-profile, available space between ground and crankshaft, as well as altitude. As soon as the oil scraper-rings have been run-in, the oil consumption of the engine will reduce drastically.

As with most carburetors, the air intake is controlled by a rotary throttle valve. A rotary throttle valve adjustment screw (1) is used to set the carburetor for the idle position. This screw should be set in such a way that the throttle is just closed when set in the idle position (check by looking through the air intake). The air flow required in the idle position is then sucked in through the idle-air-intake or 'air-bleed' hole (2). The idle air adjustment screw (3) regulates the effective size of the air-bleed. The basic setting for the air-bleed adjustment is with the end of the screw halfway across the air-bleed hole.

The fuel supply of this carburetor, which was specially designed for the FK 50, is regulated by a curve-control-system. With the carburetor correctly fine-adjusted and the glow plugs disconnected, the engine should run at 1,800 Rpm. If the engine will operate only with both glow plugs connected, the mixture is too rich. For the following fine-adjustments, please use the long socket head screw wrench supplied. Loosen the lower clamp screw (4) of the curve-control-arm (6) (steel spring). For readjusting, turn only the small idle-adjustment-screw (5):

For leaner fine setting: clockwise.
For richer fine setting: counter-clockwise.

These adjustments will cause the lower curve-control-arm to slide out of, or into, the carburetor body and thereby reduce, or enrich, the fuel supply. When the desired idle setting has been reached, tighten the lower clamp screw (4) to prevent the idle setting from accidentally being changed. With every idle readjustment on the curve-control-arm, the needle valve must be reset (leaner or richer, respectively)

After operating the engine, the oil will mix with particles of soot, of castor oil and condensed water from methanol. Therefore, we recommend (to prevent damage from corrosion):

1. An oil change after each day of flying with this engine or, alternatively, after 2 to 3 hours of operating time. It is better to change the oil while the engine is still warm.

2. Following every flying session, be sure and let the engine run at full throttle for at least one minute so that any water that may have collected in the sump can evaporate. Then pull the fuel line and let the engine run out dry.

The ignition system employs a Hall Effect (magnetic) pickup (no points to burn, oil-up or get out of adjustment) and solid state components throughout and is very reliable.

We recommend the continued use of methanol/castor fuel (as specified in the instructions) rather than a gasoline-based fuel. It is cooler running, safer and gives more power and greater reliability.

1. The ignition coil (which also incorporates the electronics) must be installed on the left side of the engine (when viewed from the front) since the screened spark plug leads are of appropriately different lengths. The three-core (red/blue/black) lead from the coil must be plugged into the four-pin left socket of the distributor (again viewed from the front). The similar (red/blue/black) lead from the micro switch must be plugged into the right socket of the distributor. Please note that the leads should be routed so that they cannot come into contact with the exhaust pipe, otherwise

insulation will be damaged - which will cause a short-circuit. From time to time, the spark plugs should be checked and, if necessary, adjusted to a gap of 0.2 - 0.3 mm

2. Ground (earth) the brown wire to one of the upper screw-5 of the intake manifold.

3. A 4.8 volt 500 ma NiCd battery pack (sufficient for approximately 1 hour of running between charges) or 4.8 volt 1,200 ma (approximately 2 hours) is required. This is not furnished with the engine and can be obtained from your local hobby shop. The battery should be connected to the two-core (black/red) lead from the coil via a regular slide switch.

Remember:

red wire to battery positive (+)

black wire to battery negative (')m

Warning: If you mix up the wiring, the electronics will be destroyed.

Note: The ignition system must be operated from its own, separate NiCd battery; do NOT connect it to the receiver battery! it is also advisable to keep the RC components (receiver, servos, battery, slide switch and wiring) as far away as possible from the ignition system.

4. Recheck all connections before applying power to the system - as already explained, an incorrect hookup will result in damage to the system.

5. The spark timing is factory-set before delivery. However, it may be adjusted as follows: Start the engine and let it run for approximately 5 minutes (engine must be warm for correct setting). You are behind the engine. While it is running, the timing can be adjusted by rotating the distributor a few degrees with the 3 mm (0.12'~ dia. steel rod supplied. Counter-clockwise movement 0.e. to the left - against the direction of propeller rotation) advances the spark; clockwise (to the right) retards it. It is not necessary to loosen the distributor retaining screws; the distributor will turn with steady pressure on the steel rod (an internal O-ring and sealing washers prevent accidental movement).

Adjusting the timing is simply a matter of advancing the spark to produce the highest full-throttle Rpm. Having adjusted the needle valve to its optimum setting, slowly turn the distributor against the direction of propeller rotation no further increase in Rpm is obtained, then turn it slowly back towards the "retard" position, but not so far as to cause Rpm to fall. This is the best running position. Experience has indicated that, at this position, the engine fires when the piston is approximately 1.5 - 2 mm (0.06 - 0.08") before top dead center. Please note that the engine revolutions at which the micro switch changes from advance to retard (and vice-versa) should be approximately 2,000 Rpm.