O.S. Type 2S & 2SB Carburettor Operational Instructions

About this manual

This manual provides operational instructions for the O.S. Type 2S and 2SB carburettors, which are slide-throttle type units designed specifically for 3.5 cc class racing car engines. The Type 2SB is intended for off-road or buggy racing, while the Type 2S is for track racing. Both models are engineered to release the full potential of O.S. MAX-21 series racing car engines.

What's inside

• Installation
• Adjustment
• Mixture Control Valve Realignment
• Carburettor Cleanliness
• Parts List

Frequently asked questions

Which engine series are these carburettors designed for?

They have been designed especially for 3.5 cc class racing car engines and release the full potential of the O.S. MAX-21 series racing car engines.

What is the difference between Type 2S and Type 2SB?

The Type 2SB is intended for off-road or buggy racing, while the Type 2S carburettor is for track racing.

What type of fuel system is required?

The carburettors are intended for operation with a muffler-pressurized fuel system, and the fuel-tank must be sealed to prevent loss of pressure.

How should the mixture control valve be adjusted if the idling mixture is too rich?

Turn the mixture control valve clockwise in increments of 30 to 45 degrees.