Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 149Get this manual
59Install ignilion coils to exhaust cover, if not previously installed with exhaust coverInspect a-ring on voltage regulator for cuts and abrasionsReplace a-ring if necessaryApply PERFECT SEAL (92-34227-1) to area of voltage regulator which contacts exhaust coverSecure voltage regulator to exhaust cover with boltsClean bolt threads wit LOCT ITE PR IMER "T" (92-59327-1)Apply LOCT ITE 222 (obtai loca lly) to bolt threads and torque bolts to 110 lbin(12.4 Nm)NOTE: If ignition components were removed individually, refer to Section for proper wiring installation 60lnstall engine temperature sender and overheat warning sensorRefer to Section wiring diagrams for proper wiring connections
aTemperature SenderOverheat Warning Sensor
NOTE: Temperature sender switch is normally pen until cylinder head temperature reaches 190 (87 .8 13.3 C) at which point it closes and the alarm ho rn is actuatedThe sender switch will remain closed until the temperature drops to 170 (76.7 13.3 C) at which point the sender switch will open and the alarm horn wi ll deactivateNOTE: Overheat warning sensor (temperature gauge sender) may be tested with digital ohmmeter by touc hing one lead to the terminal post end of sensor and th other lead to the external case of sensorAfter wa rm ing sensor in known temperatures of water, the following va lues should be obtai ned: