Chrysler 70, 75 and 85 HP Outboard Motors Service Manual OB 3438, Page 124Get this manual
CYLINDER DRAIN COVER
Throttle should be set to wide open position for this test5Note the reading on the gaugeA reading between 145-165 p.s .i(10 .2-11 .5 kgcm 2) indicates good compression If the reading is lower, then there is compression leakFigure 4
Add pounds if engine has run more than 15 hoursCYLINDER DRAIN
Figure 2Fuel Transfer within Recirculating Passages
TROUBLESHOOTING
Poor engine performance andor hard starting may be signs of compression problem Other signs include excessively smokey exhaust, badly fouled plugs, power surging or extreme power lossAll can indicate engine compression problems Therefore, when internal damage or wear is suspected as the cause of an engine problem, compression test should be done firstCompression TestFigure 3Compression Gauge Installed
Both cylinders should be within 10 P.S.Iof each otherIf greater variation is experiencedthe cylinder head should be removed and an inspection made to find the problem (fai led head gasketscored cylinderetc