.40 Cu. In. (6.44cc)


.840 (21.3mm)


.720 (18.3mm)


2,200 - 18,500


1.8 HP @ 18,500


15.4 Oz. (.44Kg)

10 X 6
Part No. 4050


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!

Due to the nature and design features of the “ABC” type engine, the piston and sleeve have been set up to feel a little tight at the top of the stroke. Once the engine has been started, the sleeve will pull away from the piston leaving the exact clearance necessary for maximum performance without seizing. It is for this reason that an “ABC” type engine does not require prolonged break-in periods. However, we do recommend that you run the engine at a slightly rich needle valve setting for the first two flights. These flights should be made for periods of not less than five (5) minutes each. Typically, an engine will be ready for continuous throttle and a steady needle valve setting after ten (10) to fifteen minutes.

The engine may be installed upright, on either side, or inverted (upside down). The 1/4-inch diameter output shaft mounts standard hole-size propellers.

Mount the engine firmly to hardwood rails, or to the firewall, if you use a radial mount. For maximum security, use carbon steel, self-locking hex nuts and hardened alloy steel machine screws to mount the engine. The fuel tank size, location, and height have a great influence on engine operation. For carburetor engines, locate the tank so that its horizontal centerline is from 1/4” to 3/8” below the fuel connection to the carburetor.

As you attach the muffler and muffler adaptor to the engine, please note that the muffler screws are different lengths. The longest screw goes on the front (propeller) end of the muffler assembly. The pressure fitting on the muffler is connected to the pressure inlet on the fuel tank.
This engine is designed to use the Long Reach Glow Plug (K&B P/N 7311) or the K&B 7300 HP glow plug for performance fuels.

We recommend using K&B 500 (12-1/2% nitro).

A 10x6p propeller is recommended as a starting size. However, experimenting with one pitch or diameter larger or smaller can improve results for your particular airplane.

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:

1. NEEDLE VALVE SET-UP - Locate an area to install the remote needle valve assembly. 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.

2. LINKAGE SETUP - Notice the barrel will rotate 360 degrees. Using your radio and trim functions, set the barrel movement for full open and full close. IMPORTANT: THE BARREL MUST CLOSE IN A CLOCKWISE ROTATION.  The opening in the barrel spraybar faces the crankshaft.


Note that there are two fuel metering adjustments:

1. HIGH-SPEED NEEDLE VALVE - 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.  WARNING: DO NOT RUN THE ENGINE AT A “LEAN” SETTING.

2. LOW-SPEED and MID-RANGE MIXTURE ADJUSTMENT - The rich/lean adjustment is controlled by the “slotted” screw located on the side of the carburetor where the low speed disk is housed. The rich/lean mixture control is set at the factory and may require only a "fine” adjustment for your application. To adjust the mixture, loosen the bottom screw (do not remove) an adjust the top slotted screw. This screw only turns 1/4 turn to either the right or left or center. It does not turn all the way around. Turn the screw clockwise to “lean” the engine and counter-clockwise to richen  the mixture. After adjusting the mixture, remember to “lock” it into position by tightening the bottom screw.

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 needle valve approximately 1/2 turn.

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