Starting

The radial movement of the centrifugal masses is transformed into an axial movement by the regulating sleeve.

The stroke of the regulating sleeve generates a thrust which varies the position of the regulating mechanism, which is made up of a control lever, tension lever and starting lever.

The control lever is housed in the shaft in the pump casing and can be adjusted by the delivery adjusting screw.

The tension and starting levers are pivoted on a common fulcrum and connected with a r.p.m. control lever. On the lower part of the starting lever, a spheric pin is fixed, which is pivoted to the adjusting cursor; whilst on the upper part, the starting spring is fixed.

The idle speed spring is fixed on the upper part of the tension lever by a pin, to which the regulating pressure spring, guided in a capsule, is hooked.

The external control lever and the internal r.p.m. control lever are fixed onto a common shaft.

The position of the regulating mechanism is defined by the common action of the spring's force and the thrust of the sleeve.

The control movement is transmitted to the regulating cursor, which determines the distributor piston delivery.

1. Centrifugal masses
2. Regulating sleeve
3. Tension lever
4. Starting lever
5. Regulating spring
6. Intermediary spring
7. Spring holder pin
8. Idle speed spring
9. Tension lever stop
10. Starting spring

Starting

The regulating sleeve is in the start position because the centrifugal masses are at rest, and for this reason the start spring pushes the start lever against the regulating sleeve.

The regulating cursor on the distributor piston is found in the start supplement position.

Regulating the idle speed

After the engine has been started and the accelerator pedal has been released, the r.p.m. control lever returns to the "idle speed" position, activated by the return spring.

As the r.p.m. increases, the centrifugal force of the masses increases, which presses the regulating sleeve against the start lever.