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 controlsystem and the fuel system.Speed Control SystemThe speed control system of an internal-combustionengine includes those parts designed to maintain theengine speed at some exact value or between desiredlimits, regardless of changes in the load on the engine.Governors are provided to regulate fuel injection so thespeed of the engine can be controlled as the load isapplied. Governors also prevent overspeeding as mayhappen in rough seas when the load is suddenly reducedas the propellers leave the water.Fuel Control RacksFuel control racks that have become sticky orjammed may cause governing difficulties. If the controlrack of a fuel system is not functioning properly, theengine speed may increase as the load is removed, theengine may hunt continuously, or it may hunt only whenthe load is changed. A sticky or jammed control rackmay prevent the engine from responding to changes inthrottle setting and may even prevent it from stopping.Any such condition could be serious in an emergencysituation. Your job is to make every effort possible toprevent such conditions from occurring.You can check for a sticky rack by stopping theengine, disconnecting the linkage to the governor, andthen attempting to move the rack by hand. There should3-36
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