This is an especially high performance engine designed for competition
in the Mono, Hydro, and Deep-V R/C boating field. 
To fully realize top performance and longer life from this high performance
racing engine, please thoroughly read and heed the following text and instructions.



.4539 Cu. In. (7.44cc)
.850 (21.6mm)
.800 (20.3mm)
2,000 - 25,000
Power Output
2.75 HP @ 25,000
1 Lb, 2 Oz. (510g)


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!



GLOW PLUG: This engine is designed to use the Long Reach Glow Plug (K&B P/N 7300).

FUEL: We recommend using 25% to 50% nitro with 18% oil.



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:


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.


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:


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.


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.
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.
All series “94” carburetors must run with exhaust pressure from the tuned pipe connected to the fuel tank.


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’s 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 runs. These runs should be made with the engine installed in the boat and running in the water for periods of not less than five (5) minutes each. Typically, an engine will be ready for continuous full throttle and a racing needle valve setting after ten (10) to fifteen (15) minutes.
The engine runs in a counter-clockwise rotation. Make certain that your starter motor is running in the same direction. With the fuel tank full, radio on, glow plug battery leads off, and your finger covering the carburetor, spin the engine with the starter for about a two second burst. This primes the engine. Now open your throttle to the starting position. Connect the glow plug battery leads and spin the engine again. The engine should fire up and run. We recommend that you be near the water when starting the engine so as not to overheat due to lack of water circulation through the cooling jacket. It is also advisable that you keep the engine at a slow, or not greater than a fast idle, until you get it into the water, as over-revving and overheating will damage your engine.

Propellers are naturally an important factor. Most propellers that are available on the market need balancing and “cleaning up”. Unbalanced props can cause cracks on boat hulls, not to mention robbing your engine of horsepower and your boat of performance. So, balancing the prop is very important. It is difficult to recommend the propeller for your particular boat, as much depends on the nitromethane percentage fuel you may use. Propeller depth and strut angle are also important factors. However, as a start, the following will have you in the ball park:

Octura No. X447 or Prather No. 240-245
Deep Vees
Octura No. X445 or Prather No. 230-235


We recommend that you use a filter in your fuel system. Install the filter on the fuel pick-up tubing between the tank and the needle valve.

At the end of each day’s running, remove the glow plug and, by spinning the engine with the starter, flush at least two ounces of fuel through the engine by holding your finger over the carburetor. Disconnect the fuel line and continue to spin the engine until dry. To prevent fuel from spraying into your eyes, keep face away from the glow plug opening, or shield the hole with a rag or towel. Next, pour an amount of after-run engine oil into the carburetor and spin the engine again for a short burst. Replace the glow plug. Remove drive cable and re-lube.

We recommend after each days running, that you check each bolt and screw for tightness.

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