1991 Johnson Evinrude EI 60 Loop V Models 150, 175 outboards Service Manual, Page 120Get this manual
Function TestsS.L.OW
This ignition system incorporates the 5.L.OWwarning system, which gradually limits engine speed to approximately 2500 RPM when engine temperature "exceeds 240 (1140 C)To resume normal operation after the 5.L.0W warning system has activated, the engine must cool to 207 (110 C) and the engine must be turned offThe 5.L.0Wwarning system depends on input from the port or starboard temperature switch tanblue leadThe 5.L.0Wwarning system is isolated from other warning horn signals by blocking diode in the engine wiring harnessTemperature Switch 1Disconnect port and starboard temperature switch tanblue leads2Install correct test propellerStart engine in test tank and run at 3500 RPM
[!] 3Touch port engine harness tan lead to clean engine ground Engine speed must gradually slow to approximately 2500 RPM4Shut off engine5Start engine and repeat Steps and using starboard engine harness tan lead Engine speed must gradually slow to approximately 2500 RPM If Steps and are normal, test temperature switchesRefer to Temperature Switch Test, Section If one of the tests is normal, check engine harness and connectors If neither test is normal, verify condition of wires and connectorsReplace power packBlocking Diode If 5.L.0Wis activated when warning horn receives no-oil, low-oil, or fuel vacuum signal, test engine harness blocking diode1Disconnect engine harness red connector2Disconnect port and starboard temperature switch tan leads3Calibrate ohmmeter on appropriate scaleConnect between either tan lead and engine harness tan pin Note reading4Reverse meter connections or press "polarity" buttonNote reading high reading in one direction and low reading in the other direction indicates diode;s good5Replace engine harness blocking diode if your test results vary6Complete all circuits disconnected during this testE