The K&B .82 cu. in. DF is a high-performance ABC type engine, designed especially for ducted fan models. It is powerful, rugged, and dependable, and will provide countless hours of sport, or competition performance if properly handled and maintained.




.8155 Cu. In. (13.4cc)
Bore 1.040 (26.42mm)
Stroke .960 (24.38mm)
R.P.M. 2,000 - 23,000
Power Output 4.2 HP @ 23,000
Weight 23.0 Oz. (652g)


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!


1.    Do not run this engine on a test stand. Nothing can be gained by so doing as you only expose yourself, and others, to possible injury from the spinning rotor.

2.    Mount the engine in accordance with the instructions supplied with the ducted-fan unit you may choose to install in your model. Make sure that it is accurately aligned and firmly bolted in place.

3.    After the complete system is installed in the airplane and all of the connections are secure and functioning, you are ready for your first engine/fan run-up.

4.    Prime the engine and turn it over once, by hand, before applying the glow plug battery, or the electric starter. (It is recommended that you have a helper hold the model while you are starting the engine). Start the engine with the throttle in the “idle” position. Avoid long periods of electric starter use. If the fuel and ignition are correct, the engine will start instantly. As soon as the engine fires, remove the starter and allow the engine to warm up at half throttle before removing the battery power from the glow plug.

5.    For the first run “DO NOT” run at full throttle for more than a few seconds. Use this run to adjust the low and mid-range setting on the carburetor. (See carburetor adjustment). When you are satisfied that the carburetor settings are correct, it is recommended that you run two or three tanks of fuel through the engine, at a slightly rich setting, before attempting your first airborne run. When you are sure that the engine will hold full power, you are ready for your maiden flight. However, to be on the safe side (to prevent possible sagging of RPM due to the engine not being fully broken in), you can achieve 98% full power with a slightly rich setting, which should not impair the flying of the model.


If you are unfamiliar with this line of carburetors or are a new modeler, please do not attempt to start the engine until you have read and understand the following instructions:

The carburetor enables easy adjustment of the idle speed, idle mixture and the high speed mixture.


Locate an area to install the Remote Needle Valve Assembly using the bracket provided. This may typically be attached to the firewall, cowl, or rear engine mount lug area. This assembly must be in the fuel line between the tank and the carburetor. The line should not exceed five (5) inches in total length.


This needle valve, located on the Remote Needle Valve Assembly, controls all the fuel that comes to the engine, whether the engine is running at high, mid-range, or idle-speeds. It does not affect the low speed rich/lean setting. The High Speed Needle Valve’s main function, however, is to meter the high-speed fuel mixture.
As a starting point for the High Speed Needle Adjustment, completely close the needle valve (clockwise), then open it (counter-clockwise) three and a half turns. This setting is an average and may require further adjustments. For higher altitudes (3,000 - 4,000 feet), close the needle valve approximately 1/2 turn.


The rich/lean adjustment is controlled by the brass low speed disk located on the side of the carburetor. Using the allen wrench provided, turn the disc clockwise to “lean” the mixture and counter-clockwise to “richen” the mixture. The rich/lean mixture control is set at the factory and may require only a fine adjustment for your application. WARNING: DO NOT RUN THE ENGINE AT A “LEAN” SETTING.
All series “94” carburetors must run with exhaust pressure from the pipe to the fuel tank.
We recommend the use of K&B 515 DF fuel which is specifically blended for Ducted Fan usage. Use of inexpensive, or poorly mixed fuels will seriously detract from the life of this engine. We also recommend the use of an after-run oil, such as Zap, Marvel Mystery, or automatic transmission fluid for protection of the bearings, and other steel components in the engine, after each day’s flying, or while it is not being used for some time.

The Exhaust extension supplied with this engine will work with most tuned pipes available. However, the tuned pipe most recommended to us (by those who have been running the K&B .82’s) is the MAC 10-13cc tuned pipe. The pressure tap fitting should be located in the center of the highpoint of the tuned pipe and routed to the fuel tank with a medium size silicone fuel line.

Should you utilize either a large single tank or twin tanks with or without a hopper/surge tank, please make sure you have a constant fuel supply to the carburetor. If you use “Pitot” pressure, remember the pressure drops as the fan speed reduces, which can cause a lean condition. You may require larger lines on the pressure side or your system. If you have a large capacity fuel system, the pressure drops as fuel is replaced with air, which can cause a lean condition. An in-flight needle valve assembly (such as K&B P/N 9275) is recommended for use if you are unsure of your fuel delivery system.
Glow plug life is a function of time and of how hard you run the engine. Lean runs are the quickest way to burn out a glow plug. This engine is equipped with a No. 7311 KB-IL which is a hot-type racing plug. There are many good colder glow plugs available so you should experiment to find one that you feel is most effective. Head shims are available and may be used under different atmospheric conditions, and for different fuels that can affect the glow plug life.

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