Service Manual
25
GTS 200
Governor
Governor
Contents
General
Information
25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Governed RPM Limits
25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mechanical Governor
25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassemble 25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspect Governor
26
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assemble Governor Crank
26
. . . . . . . . . . . . . . . . . . . . .
Install Crankcase Cover or Sump
26
. . . . . . . . . . . . . . . .
Adjust T
op No Load RPM
26
. . . . . . . . . . . . . . . . . . . . .
Seal Protectors
26
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General
Information
The
governor spring tends to pull the throttle open. The force
of the counterweights, which are operated by centrifugal
force, tends to close the throttle. The engine speed at which
these two forces balance is called the governed speed. The
governed speed can be varied by changing governor spring
tension or governor spring, Fig. 42.
1
Fig. 42
– Governor Spring
(blower housing removed)
1. Governor
spring
Governed
RPM Limits
To
comply with specified top no-load speed limits, engines
use either calibrated governor springs or an adjustable top no
load speed. Calibrated springs or an adjustable top no load
speed limit will allow no more than a desired top governed
speed when the engine is operated on a rigid test stand.
However
, the design of the cutter blade, deck, etc., can af
fect
engine speeds. Therefore, the top no load speed should be
checked with a tachometer when the engine is operated on a
completely assembled machine. The RPM should be measured
with the mower on a hard surface to eliminate cutting load on
the blade.
If a governor spring must be replaced, consult the appropriate
T
oro Illustrated Parts List.
CAUTION
AFTER A new governor spring is installed, check
engine top no load speed.
Run engine at half throttle to allow the engine to reach normal
operating temperature before measuring speed with a
tachometer.
T
oro rotary mowers should be set to run at 3,000 RPM
150,
which will produce blade tip speeds of 19,000 feet per minute.
If a service replacement engine is used, check the top no load
speed with the engine operating on a completely assembled
mower
. If necessary
, change the governor spring or adjust the
top no load speed limit device, so the engine will not exceed
the recommended speed. See page 26 for adjustment
procedure for mechanical governor
.
Mechanical
Governor
The
mechanical governor used is illustrated in Fig. 43, and is
part of the oil slinger assembly
. The governor crank is
mounted in the cylinder assembly
.
1
2
3
4
Fig. 43
– Governor
1. Governor
cup
2.
Governor weight pins
3.
Governor gear and oil
slinger
4.
Governor crank
Disassemble
1. Before
governor can be serviced, drain oil from engine and
remove crankcase sump, page 53.
2.
Loosen governor lever bolt and nut, Fig. 44.