Stihl BT 121 User Manual

1BT 121
English / USA
BA_SE_175_008_01_03.fmPrinted on chlorine-free paper.
Printing inks contain vegetable oils; paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2006 0458 428 8621 A. M1. L6. T. Printed in Germany
STIHl
Contents
Guide to Using this Manual .............. 2
Safety Precautions and
Working Techniques ......................... 3
Assembling the Machine ................ 11
Adjusting the Throttle Cable ........... 11
Fuel ................................................ 12
Fueling ............................................ 13
Auger Brake ................................... 14
Fitting the Auger ............................. 15
Starting / Stopping the Engine ........ 15
Operating Instructions .................... 18
Releasing a Trapped Auger ............ 19
Cleaning the Air Filter ..................... 19
Motor Management ........................ 19
Adjusting the Carburetor ................ 20
Checking the Spark Plug ................ 21
Engine Running Behavior ............... 22
Lubricating the Gearbox ................. 22
Replacing Starter Rope
and Rewind Spring ......................... 23
Storing the Machine ........................ 25
Maintenance Chart ......................... 26
Main Parts and Controls ................. 27
Specifications ................................. 28
Maintenance and Repairs ............... 30
STIHL Incorporated
Federal Emission Control
Warranty Statement ........................ 31
Allow only persons who understand this
manual to operate your earth auger.
To receive maximum performance and
satisfaction from your STIHL earth
auger, it is important that you read and
understand
the maintenance and safety
precautions
, starting on page 3, before
using your earth auger.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
!Warning!
Because an earth auger is a high-
torque, gasoline-powered tool, some
special safety precautions must be
observed to reduce the risk of personal
injury.
Careless or improper use may cause
serious or even fatal injury.

Stihl BT 121 Specifications

Engine Specifications

displacement	30.8 cm3
bore	35 mm
stroke	32 mm
engine power	1.3 kW
max engine speed without drilling tool	12, 300 rpm
engine idle speed	2, 800 rpm

Sound and Vibration

sound pressure level	101 dB (A)
sound power level	107 dB (A)
vibration left handle	2.6 m/s2

Ignition System

electrode gap	0.5 mm
spark plug thread	M 14 x 1.25; 9.5 mm long
spark plug	Bosch WSR 6 F, NGK BPMR 7 A, Champion RCJ 6 Y

Fuel System

fuel tank capacity	0.64 l
carburetor type	All position diaphragm carburetor
air filter	Paper filter element

Drilling Gear

gear type	Two-stage spur gear drive
gear ratio	47.5:1
max spindle speed	190 rpm

Weight and Dimensions

weight without drilling tool	9.4 kg
length of unit	400 mm
width of handle frame	530 mm