This manual introduces the use of the O.S. TYPE 3H automatic carburetor
This manual provides instructions for the O.S. Type 3H automatic carburettor, which features an automatic mixture control device to ensure a balanced fuel-air mixture at all throttle settings. It details the function of three adjustable controls: the Needle-Valve, the Mixture Control Screw, and the Throttle Stop Screw. The document includes provisional settings for both fixed-wing aircraft and helicopters.
| Control Features | Three adjustable controls: Needle-Valve, Mixture Control Screw, Throttle Stop Screw |
|---|---|
| Needle-Valve Setting (Fixed-Wing) | 1 1/2 to 2 turns from fully closed position |
| Needle-Valve Setting (Helicopter) | 2 1/2 turns from fully closed position |
| Seal Dimensions | 2.5 mm bore, 5.0 mm outer dia., 7 mm length |
Open the Needle-Valve 1 1/2 to 2 turns from the fully closed position.
Open the Needle-Valve 2 1/2 turns from the fully closed position.
It is used for manually adjusting the automatic mixture control valve to obtain a stable idle and smooth transition through the medium speed range.