1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 152Get this manual
Thermostat Wash thermostat with cle an waterUsing thermostat tester, similar to the one shown, test thermostat as follows: pen thermostat valve, then insert thre ad betwe en valve and thermostat bodyAllow valve to close against thre ad
Reed Blocks
NDo not disassemble re ed block unless necessaryIt may be necessary to apply he at to bolt (e) to soften Loctite before removal
S Suspend thermostat (from thre ad) and thermometer inside tester so that neither touches the containerBottom of thermometer must be even with bottom of thermostat to obtain correct thermostat openingS Fill thermostat tester with water to cover thermostatO bserve temperature at which thermostat begins to openThermostat will drop off thre ad when it starts to openThermostat must begin to open when temperature re aches 5_ (3_ C) above designated stamping on bottom of thermostatC ontinue to he at water until thermostat is completely open