Chrysler 75 and 85 HP Outboards Service Manual OB 3646, Page 124Get this manual
CYLINDER DRAIN COVER
Throttle should be set to wide open position for this test5Note the reading on the gauge 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 leak Figure 4
CYLINDER DRAIN REED PLATE
Add pounds if engine has run more than 15 hours
CYLINDER DRAIN
Figure 2Fuel Transfer within Recirculating Passages
TROUBLESHOOTING
Poor engine performance andor hard starting may be signs of compression problemOther 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 first Compression Test
Figure 3Compression Gauge Installed
Both cylinders should be within 10 P.S .1of each otherIf greater variation is experiencedthe cylinder head should be removed and an inspection made to find the problem (failed head gasket, scored cylinder, etc