Figure 3-40.Possible troubles that may cause an engine to stall frequently or to stop suddenly.
are caused by troubles originating in the speed control
system and the fuel system.
Speed Control System
The speed control system of an internal-combustion
engine includes those parts designed to maintain the
engine speed at some exact value or between desired
limits, regardless of changes in the load on the engine.
Governors are provided to regulate fuel injection so the
speed of the engine can be controlled as the load is
applied. Governors also prevent overspeeding as may
happen in rough seas when the load is suddenly reduced
as the propellers leave the water.
Fuel Control Racks
Fuel control racks that have become sticky or
jammed may cause governing difficulties. If the control
rack of a fuel system is not functioning properly, the
engine speed may increase as the load is removed, the
engine may hunt continuously, or it may hunt only when
the load is changed. A sticky or jammed control rack
may prevent the engine from responding to changes in
throttle setting and may even prevent it from stopping.
Any such condition could be serious in an emergency
situation. Your job is to make every effort possible to
prevent such conditions from occurring.
You can check for a sticky rack by stopping the
engine, disconnecting the linkage to the governor, and
then attempting to move the rack by hand. There should