Chrysler 100, 115 and 140 HP Outboard Motors Service Manual, OB 3439, Page 126Get this manual
CYLINDER DRAIN REED PLATE CYLINDER DRAIN COVER #1 CYLINDER (#3 CYLINDER)
3Insert the tip of the compression tester into the spark plug hole of the cylinder being testedFigure 3
Throttle should be set to wide open position for this test 4Crank the engine over with the starterLet the engine crank over several times to make sure that each cylinder comes up forthe compression portion of its stroke several times5Note reading on the gauge as followsCompression Readings 100 .PGood145-165 PSI (10 .2-11.6 kg cm 2) 115 .PGood125- 145 P.S .I(8.8-10 .2 kg cm 2)
TO #1 CYLINDER (TO #3 CYLINDER)
140 .PGood150-165 P.S.I(10 .55- 11.6 kgcm 2) If the reading is lower, then there is compression leak Figure 4
#2 CYLINDER (#4 CYLINDER)
Add pounds if engine has run more than 15 hours