Stihl BT 131 - Servicing Precautions

BT 131 3
4.1 Clutch
4.2 Auger Brake
4.3 Gearbox
4 Troubleshooting
Condition Cause Remedy
Auger stops under full load Clutch shoes badly worn Replace clutch
Clutch drum badly worn Install new clutch drum
Auger runs while engine is idling Engine idle speed too high Reset idle speed screw (LA) correctly
Clutch spring fatigued Replace spring / clutch
Clutch spring broken Replace spring / clutch
Loud noises Clutch spring fatigued Replace spring / clutch
Clutch drum bearing damaged Replace ball bearing in clutch housing
Clutch screws loose Tighten down screws, replace clutch if nec-
essary and check tapped holes in flywheel,
replace flywheel if necessary
Clutch shoes worn Replace clutch
Condition Cause Remedy
Auger stops under full load Brake band jammed Check freedom of movement and function
of brake band, replace if necessary
Auger does not stop immediately
when auger brake is engaged
Auger brake spring stretched or broken Fit new auger brake spring
Brake band stretched, worn or broken Replace brake band
Clutch drum worn Install new clutch drum
Condition Cause Remedy
Loud noises Ball bearings damaged or worn Inspect bearings in clutch housing and
gearbox, replace if necessary
Pinion / output shaft or gears damaged or
worn
Replace pinion set at input and output
sides
Insufficient or no grease in gearbox and/or
clutch housing
Replace pinion set at input and output
sides
Gearbox too hot Excessive friction due to damaged or worn
ball bearings
Inspect bearings in clutch housing and
gearbox, replace if necessary
Insufficient or no grease in gearbox and/or
clutch housing
Check pinion shaft, output shaft and gears
for damage, replace if necessary, then
pack gearbox and clutch housings with
STIHL gear grease
Gearbox runs erratically and stops
under load
Clutch worn Inspect clutch and clutch drum, replace if
necessary
Gearbox jammed Damaged or worn ball bearings have
seized
Inspect bearings in clutch housing and
gearbox, replace if necessary
Teeth damaged or broken – pieces are
causing blockage
Check pinion shaft, output shaft and gears
for damage, replace if necessary – always
replace both meshing components