1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 191Get this manual
Testing Temperature Switch(es) Remote Control Models Temperature switches, insta led in each cylinder head, are in series with warning horn in the remote control box Should an irregularity develop in the cooling system and cause abnormal water jacket temperatures, the switches close the warning circuitA switch may be checked by submerging it in hot oilUse test light to check the contacts and thermometer to check oil temperatureThe contacts should close at temperature of 99 30 (211and open at 790C 40 (175 )To remove switches for testing, pull back insulating sleeves and open knife terminal connectionsRemove cylinder head cover(s) and switch(es)On installation, clean gasket surface thoroughlyApply OMC Gasket Sealing Compound lightly to gasket surface(s)Also apply the same sealing compound to top surface of heat switch grommet and again after cover has been installedInstall cylinder head cover using new gasketReconnect temperature switch leads and slide insulating sleeves over connections