How to test if "hot" light is weak

stevejeri

Seaman Apprentice
Joined
Aug 12, 2007
Messages
44
Just replaced the impeller on 68 85hp Evinrude, but hot light still comes on after a couple minutes idleing. How do I test to see if the light is working properly and do they get weak over time to where it isn't really hot? If it is working properly, what would cause one to get hot? I made sure the copper tubes lined up when I put the lower unit back on, and I ran water through tubes with garden hose when I had lower unit off and all was clear.
 

seahorse5

Rear Admiral
Joined
Jan 24, 2002
Messages
4,698
Re: How to test if "hot" light is weak

The first thing to do is to find out how hot the motor is getting at idle.

Use an infrared temp gun or the Thermo-melt sticks to see if the cylinderheads are getting above 140? or so. You may have a thermostat problem, leaking head gasket, etc.
 
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