Governor - Kubota WG972-E2 Workshop Manual

WG972-E2, DF972-E2, WSM

[5] GOVERNOR

The engine is equipped with a centrifugal ball
mechanical governor which activates the throttle in
response to engine speed.
When the engine is carrying a load and running at
rated speed, the speed will drop if the load is increased
even slightly. In this case, the governor automatically
opens the throttle valve of the carburetor to maintain the
original speed.
Dumping the load suddenly will cause a rapid
increase in speed.
automatically moves the throttle valve in closing direction
to prevent the engine from increasing its speed.
1) When engine is carrying a load and running at
rated speed
When there is no change in load, the centrifugal force
of the ball (6) which is attached to the governor gear (4)
balances with the tensile force of the governor spring (8)
via governor sleeve (5), fork lever (7), governor lever
shaft (3) and governor lever (2). The engine speed and
output are thus kept constant.
2) When load is applied to engine
When the load is applied to the engine running at
rated speed, the speed of the governor gear (4) which is
connected to the idle gear decreases. As a result, the
centrifugal force of the ball (6) becomes smaller. The
tensile force of the spring (8) overcomes the centrifugal
force, and the governor lever (2) causes the throttle lever
(1) to move in the open direction (B). The original engine
speed is thus maintained.
3) When load is dumped
When the load is dumped suddenly, the centrifugal
force of the ball (6) overcomes the tensile force of the
spring (8). As a result, the governor lever (2) causes the
throttle lever (1) to move in the shut direction (A) and
prevents the engine from increasing its speed.
(1) Throttle Lever
(2) Governor Lever
(3) Governor Lever Shaft
(4) Governor Gear
(5) Governor Sleeve
(6) Ball
(7) Fork Lever
M-20
GASOLINE / LPG ENGINE
In this case, the governor
(8) Governor Spring
(9) Speed Control Lever
(10) Carburetor / DF Carburetor
A : Shut Direction
B : Open Direction
W1014969
KiSC issued 01, 2006 A