Instructions for
Part No. 5390
Released on March 1999



Displacement .9123 Cu. In. (14.9cc)
Bore 1.100 (27.94mm)
Stroke .960 (24.38mm)
R.P.M. 2,000 - 22,000
POWER OUTPUT 4.8 H.P. @ 22,000
Weight 23 Oz. (652g)
Propeller P-260


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!


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.

1.    Mixture Control (High Speed Needle Valve) Assembly

This engine comes with a servo actuated servo mixture control. Should you desire to use a standard Needle Valve Assembly, return your new, unused Mixture Control Assembly and we will replace it with a standard Needle Valve.

2.    High Speed Needle Valve Adjustment

This needle valve, located on the Mixture Control 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.
When preparing to use the Mixture Control, open the High Speed Needle Valve three and one half (3-1/2) to four (4) turns, unscrew the plastic body from the aluminum housing one (1) full turn and connect the servo linkage. Adjust the servo arm on the Mixture Control to best suit your needs for the engine operating range you require. The High Speed Needle Valve is for course adjustment and the servo arm is for fine adjustments.

3.   Low Speed and Mid-Range Adjustment

The rich/lean adjustment is controlled by the brass low speed disk located on the side of the carburetor. Use an allen wrench to 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.

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:

Prather No. 270
Deep Vees
Prather No. 260
Tuned Pipes
Prather No. 9040 or Mac’s No. 1290


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

FUEL: We recommend using K&B 1000+, 25% nitro.

HEAD SHIMS: The head clearance of your engine has been checked and set as close as possible to 18 thousandths of an inch. A shim may have been installed under the head to achieve this. Please replace them should you need to disassemble the engine for any reason.

REMEMBER: Check all bolts on engine for tightness after each run.


©2008-1998 Model Engine Corporation of America, All rights reserved.
K&B and the oval logo are Registered Trademarks of Model Engine Corp. of America
Registered U.S. Patent Office

No part may be reproduced without written permission from
MECOA/K&B -- P.O. Box 98 -- Sierra Madre, CA 91025 U.S.A.