1998 Johnson 25 hp - How do you test the temperature switch?

[Hometime]

Have a 1998 Johnson 25 hp, Model# J25RMLECA , Maual Start , No key

Replaced thermostat , water pump , new plugs ....
How do you test the temperature switch?
Can you by pass switch?
Took off the oil ejection system , recommended by dealer, mix gas and oil now...
Will not go over 2500 rpms..

Thanks

 

[hidef]

Re: 1998 Johnson 25 hp - How do you test the temperature switch?

First off you need really need the OMC service manual for working on these outboards. The temperature sensor is located between the top and middle cylinder. It is connected in series with the warning system. I do not know if disconnecting the switch will disable the SLOW mode. To test the switch you need Ohmmeter a reliable thermometer and a container of 4 stroke motor oil you should use synthetic with a boil temp over 300 degrees F. You have to place the switch in the oil and heat it to test the switch.

Tan/Blue switch closed 240 F + or - 6 switch open 207 F + or - 15
white/black switch closed 105 F + or - 3 switch open 90 F + or - 3