Technical Information  08.2005 Page 17
TI_08_2005_11_01_02.fm
5.5 Test the compression pressure
In order to discharge the ignition voltage, 
the ZAT 3 5910 850 4520 ignition system tester 
must be mounted – high voltage shock hazard!
. Remove the ignition system tester from the 
spark plug, and screw out the spark plug.
. Screw in compression tester 5910 850 2000 (1) 
into the sparkplug hole.
. Connect the spark plug boot to the high voltage 
terminal (1).
. Affix the ground terminal (2) to the muffler.
. Set the knob (3) for the spark gap to 
approx. 2 mm.
While using the ZAT 3, hold it only by the handle (4) 
or position it in a safe place. Fingers and other body 
parts must be at least 1 cm away from the spark 
window, high-voltage terminal, ground connection 
and ground terminal. 
. Pull the rewind starter quickly and forcefully 
(min. 1,000 rpm) as when starting.
. Read the compression – 
the target is 7.5 ... 8.5 bar
If the compression is under 7.5 bar 
. Check valve clearance, set if necessary and 
recheck the compression
If the compression is still under 7.5 bar 
. Check the cylinder, valve seat, piston and piston 
rings for scoring and damage.