Specifications

36
TVT / VTX / OV691 Governors and Linkage
General Information
The TVT / VTX / OV691 engine is equipped with an
internal mechanical governor. The governor’s function
is to maintain a R.P.M. setting when engine loads are
added or taken away. This chapter includes governor
assembly linkage illustrations to aid in governor or
speed control assembly.
Operation
As the speed of the engine increases, the weights
on the governor gear move outward from centrifugal
force lifting the governor spool. The contact between
the spool and governor rod causes the attached outer
governor lever to push the solid link and close the
throttle plate. When the engine speed decreases, the
lower centrifugal force allows the governor weights to
be pulled in by the governor spring. The governor rod
rotates and the solid link moves the throttle plate to a
more open position (diag. 66).
Troubleshooting
NOTE
Engine overspeed must be corrected immediately,
before serious engine damage occurs.
Erratic engine operation where the governor is suspect,
may be the result of other engine system problems.
Hunting (engine R.P.M. surging up and down) can be
an indication of fuel starvation or an air leak. Low power
(engine will not hold R.P.M. under load) can indicate,
fuel, ignition or internal concerns. Use the following
procedure to diagnose a suspected governor problem.
Engine Speed Adjustments
Before attempting to set the governed high or low
R.P.M. speeds, locate the recommended R.P.M.
setting according to the engine model and specification
numbers.
To avoid serious injury, and engine or
equipment damage, DO NOT exceed
the factory recommended R.P.M. engine speed. Doing
so can be dangerous and will VOID THE ENGINE
WARRANTY.
NOTE
Factory recommended R.P.M. engine speed
specifications can be located on microfiche card #30 or
the computerized parts look-up system.
Start the engine and allow it to warm up to normal
operating temperature (3 - 5 minutes). Set the speed
control to the low speed position. Check the governed
idle speed (not true idle). Adjustment is made by
bending the governor spring bracket upward to increase
the idle R.P.M. or downward to lower idle R.P.M.
(diag. 67).
Set the speed control to the HIGH or FAST position.
Check engine speed. To adjust, bend the tang on the
control lever upward to increase high speed R.P.M. or
downward to lower high speed R.P.M. (diag. 68).
THROTTLE
GOVERNOR
SHAFT
WEIGHTS
SPRING
GOVERNOR
SPOOL
GOVERNOR
LEVER
GOVERNOR
GEAR
66
GOVERNED IDLE
SPRING BRACKET
67
68
WARNING
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