Technical Information · issue 32 of 1994
Service: STIHL ZAT 3 ignition tester
IssueTI 32/1994
Full text
Page 1 of 2
Technical Information
32.94
STIHL Workshop Service
STIHL ZAT 3 Ignition Tester
The new ZAT 3 is a practical, handy and inexpensive tester that every repair shop can afford and should
have. It can be used for simple, fast and conclusive testing of ignition systems on all STIHL gasoline
powered chain saws and power tools.
Important: Please state the diagnosis obtained with ZAT 3 on warranty claims submitted for faulty ignition
modules.
The ZAT 3 can be connected in two ways:
Either as a main spark gap between the ignition module (or ignition coil) and ground for an ignition test
without running the engine
Or as an auxiliary spark gap between the ignition module (or ignition coil) and spark plug for an ignition
test while engine is running.
1. Operating Instructions
5
Connect engine’s spark plug terminal (1) to ZAT
high tension terminal (2)
Connect plug cap (3) of connecting lead (4) to
ground terminal (5) on the ZAT 7
2 9
1.1 Using as main spark gap
Unscrew the spark plug. 4 3
Connect alligator clip (6) of connecting lead (4) 1
to cylinder fin or other suitable ground point on
engine. 7
Use adjusting knob (7) to set spark gap to 6 mm.
Give the starter rope a quick pull.
Evaluate condition of spark through spark 6
window (8):
- No spark - ignition system faulty. 8 9
- Spark - ignition system is in order. Page 2 of 2
Technical Information 32.94 - Page 2
1.2 Using as auxiliary spark gap
Connect alligator clip (6) to spark plug.
Use adjusting knob (7) to set spark gap to 2 mm.
Hold ZAT by its handle (9) or put it down so that 4 3
it does not move while the engine is running. 1
Crank the engine as described in the owner’s
manual. 7
When engine starts, evaluate auxiliary spark
through spark window (8):
- Steady, uniform spark - ignition system is in 6
order.
- Intermittent spark - ignition system faulty. 8 9
If engine does not start, evaluate spark through
spark window (8):
- No spark - ignition system faulty
- Spark - ignition system is in order.
Look for fault in fuel supply, for example.
1.3 Precautions
• Never operate this ignition tester near flamma- • This
ignition tester must never be operated by
ble substances (fuel, gas, etc.) - fire hazard! children or anyone not properly instructed in
its use.
• Never operate this ignition tester with wet
• Never
hands - risk of electrocution! turn the spark gap adjusting knob (7)
• While
beyond its end position as this could damage
using the tester, only hold it with the the electrodes.
knurled handle (9). To avoid the risk of electro-
• Evaluation
cution, keep your fingers and other parts of of the spark is difficult in bright
your body at least 1 cm away from the spark conditions. We recommended that you
window (8), the high tension terminal (2), blacken the spark window on one side or at
ground terminal (5) and the alligator clip (6). least hold the ZAT against a dark background.
• When using the tester as an auxiliary spark
gap the engine will start when the starter is
actuated - observe general safety precautions
and notes in power tool owner’s manual.
2. Summary
Part Name Original New Key Rem. MOQ
version version H
ZAT 3 ignition tester --- 5910 850 4520 1
Last Technical Information on Workshop Service: 06.93
Waiblingen, June 15, 1994 Andreas Stihl
D1/MTK Technical Documentation
... Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.