Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 156Get this manual
Checking Connecting Rod Oil Clearance 1Clean all the oil from the connecting rod and bearing surface on the crankshaftCheck for pitting, scoring and discoloration2Install the connecting rod to the respective crank pin3Place piece of plastigauge on the crank pin
5Remove the connecting rod cap and measure the compressed plastigauge to check the connecting rod oil clearanceOut of specification, replace
Connecting Rod Oil Clearance 0.00080.0018 in(0.0210.045 mm)
Thermostat
IMPORTANT: Do not rotate connecting rod andor crankshaft when measuring clearance4Install the connecting rod capTorque bolts in sequence and in two steps1Push open the thermostat valve and place piece of thread into the valve2Suspend thermostat in waterHeat water slowly while observing thermometer