Chapter 4 Governors And Linkage - Tecumseh ECV100-120 - TECHNICIAN S Handbook

CHAPTER 4 GOVERNORS AND LINKAGE

GENERAL INFORMATION
This chapter includes governor assembly and linkage illustrations to aid in governor or speed control assembly.
Tecumseh 4 cycle engines are equipped with mechanical type governors. The governor's function is to maintain a
constant R.P.M. setting when engine loads are added or taken away. Mechanical type governors are driven off the
engine's camshaft gear. Changes in engine R.P.M. cause the governor to move the solid link that is connected from
the governor lever to the throttle in the carburetor. The throttle is opened when the engine R.P.M. drops and closes as
the engine load is removed.
OPERATION
As the speed of the engine increases, the governor
weights (on the governor gear) move outward by
centrifugal force. The shape of the governor weights force
the governor spool to lift. The governor rod maintains
contact with the governor spool due to the governor spring
tension. As the spool rises, the governor rod rotates,
causing the attached outer governor lever to pull the solid
link and close the throttle opening. When the engine
speed decreases, the lower centrifugal force allows the
governor weights to be pulled in by the governor spring.
As the spool lowers, the governor rod rotates and the
solid link pushes the throttle to a more open position (diag.
1).
INTERNAL COMPONENTS (VARIOUS STYLES)
2
TROUBLESHOOTING
Engine problems where the governor is suspected to be the cause, may actually be the result of other engine system
problems. Hunting (engine R.P.M. surging up and down) indicates that the engine is incapable of maintaining a
constant R.P.M. with or without an engine load. Engine overspeeding (either with or without throttle movement) must
be corrected immediately before serious engine damage occurs. Use the following procedure to diagnose a suspected
governor problems.
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SPOOL
SHAFT
GEAR ASSY.
(GOV.)
WASHER
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