« Back to Dictionary Index

The temperature compensator in SU carburetors is an ingenious mechanism designed to maintain optimal air-fuel mixture ratios despite variations in underhood temperature.

  1. Wax-Type Thermostat: The temperature compensator contains a wax-type thermostat, which is sensitive to changes in temperature. As the underhood temperature increases, the wax inside the thermostat expands.
  2. Jet Adjustment: Connected to the thermostat is a mechanism that adjusts the position of the carburetor’s jet head. When the wax inside the thermostat expands due to higher temperatures, it pushes against this mechanism, causing the jet head to move upwards.
  3. Fuel Flow Regulation: By moving the jet head upwards, the effective area of the jet is reduced. This reduction in the jet’s effective area limits the amount of fuel flowing through the carburetor, compensating for the decrease in fuel viscosity caused by higher temperatures.
  4. Maintaining Optimal Mixture: The temperature compensator ensures that the air-fuel mixture remains at the correct ratio even as underhood temperatures fluctuate. This is crucial for maintaining engine performance and reducing emissions, especially during idling when precise air-fuel mixture control is essential.

Overall, the temperature compensator in SU carburetors demonstrates an elegant solution to the challenge of maintaining consistent engine performance under varying operating conditions.

« Back to Dictionary Index