AMK853 Venturi control unit assembly.

If your Nuffield 3DL engine is surging it could be caused by a worn Venturi control unit assembly.

The Venturi control unit is fitted in the inlet manifold and contains a butterfly valve which is connected to the driver’s accelerator pedal. This controls the engine speed to a steady rate. 

For the BMC 2.6 litre 3 cylinder engine and a pneumatic governed injector pump.

See item number 7 in the diagram.

Fitted to tractors:

• Nuffield 3DL (Universal Three)