Fast Idle Unloader

Fast Idle Unloader Description
The fast idle cam is engaged by depressing the accelerator pedal, and is disengaged by the fast idle unloading mechanism.











Operation
The fast idle unloader has two diaphragms to release the throttle valve in two steps. When the coolant temperature reaches the set temperature of thermovalve A-stage 1, port B closes to shut off the vacuum bleed. This allows the inside diaphragm of the unloader to retract to the first step by manifold vacuum. Then, as the coolant temperature rises further and reaches the set temperature of thermovalve A-stage 2, the vacuum bleed flows through port A and port B and manifold vacuum is applied to the outside diaphragm of the unloader. This allows the unloader to retract to the second step.