John Deere stx38 - Manual (Page 51)

4/23/97
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ENGINE TESTS AND ADJUSTMENTS
GOVERNOR ADJUSTMENT
Reason:
To make sure the governor shaft contacts the fly-
weight plunger when the engine is stopped.
NOTE: Adjust throttle cable before adjusting governor
linkage.
Procedure:
1. Move throttle lever to FAST idle position.
2. Loosen nut (A).
3. Hold top of governor arm (B) toward carburetor.
Turn governor shaft (C) counter-clockwise until it
stops. Hold governor shaft and tighten nut.
4. Move throttle lever through full range to be sure
linkage is not binding.
5. Governor spring (D) should be installed in the hole
closest to governor shaft. If governor is not
responding properly, replace spring and readjust
fast idle speed. If spring did not correct the
problem, repair governor.
FAST IDLE SPEED ADJUSTMENT
Reason:
To set engine fast idle rpm.
Equipment:
• JTO5719 Photo Tachometer
Procedure:
1. Move transaxle shift lever to neutral position.
Engage park brake.
2. Put reflective tape on blower housing screen.
3. Start and run engine at MEDIUM idle for five
minutes.
4. Move throttle lever to FAST idle position.
5. Align holes of throttle lever and throttle control plate
with 6.4 mm (0.25 in.) drill bit (A). This keeps the
throttle control lever from moving during
adjustment. Be sure drill bit is perpendicular to the
throttle control plate.
6. Use a photo tachometer to check engine rpm at the
blower housing screen.
Specifications:
Domestic fast idle speed setting . . . 3350 ± 50 rpm
Export fast idle speed setting . . . . . . 3000 ± 50 rpm
Control panel screw torque. . . . . 9.9 N•m (88 lb-in.)
Results:
• If fast idle speed does not meet the specifications,
loosen cap screws (B).
• Move throttle control plate (C) upward to increase
rpm or downward to decrease rpm.
• Hold the throttle control plate and tighten cap
screws.
D
A
C
B
M55935
c
CAUTION
Engine will be HOT. Be careful not to burn skin.
B
C
A
M55933