Suzuki outboard motors 1988 2003 repair manual., Page 29Get this manual
MAINTENANCE 3-13 Fig33 Removing the high tension leadAlways use twist and pull motion on the
Fig34 All spark plugs should be grounded while making compression teststhis action will prevent placing an extra load on the ignition coil
04702P04
05003P26
Fig35 Crank the engine with the starter through at least complete strokes with the throttle at the wide-open position, to obtain the highest possible reading
5Insert compression gauge into the No1, top, spark plug opening6Crank the engine with the starter through at least complete strokes with the throttle at the wide-open position, to obtain the highest possible readingThen record the reading7Repeat the test and record the compression for each cylinder8A variation between cylinders is far more important than the actual readingsA variation of more than 15 psi (103 kPa), between cylinders indicates the lower compression cylinder is defectiveNot all engines will exhibit the same compression readingsIn fact, two identical engines may not have the same compressionGenerally, the rule of thumb is that the lowest cylinder should be within 25 of the highest (difference between the two readings)9If compression is low in one or more cylinders, the problem may be worn, broken, or sticking piston rings, scored pistons or worn cylindersISee Figure 36