engine heat yamaha 90 hp

[chompin]

my heat sensor activate the alarm (buzzer )
how can i know if the problem is with the sensor or the temp is getting to high.

[Hamfisted]

Take the sensor off and test it in a hot pot of water on the stove. Use a cooking thermometer and ohm meter. The two wires should have no continuity (open circuit...) until approx. 183F-194F degrees temperature. Above that temperature they should have continuity (triggering the alarm horn...). Also you can check the actual heat of the motor if the sensor is functioning properly, using an infra-red thermometer pointed at the head area of the motor.
Are you seeing a good tell-tale water stream from the motor when it's running?


-Mike

[chompin]

yes there is a good tell-tale stream .
when the alarm starts i can put my hand on
the head and around thermostat for 2 - 4 second is that a sign for a reasonable temp?
but i will try to get a thermometer to test the sensor

[jonp]

Hello,

I have a 90 HP yam, and had an over heat problem. you should be able to touch the engine block when hot without being too uncomfortable. Mine was on the verge seting off the sensor, because an old piece of an impeller was stuck in the water tube. Very hard to figure out. It also did put out very good stream of water. Don't be fooled by the water steam. I also had a smaller yamaha and an big V6 merc that both needed a water pump yet put out plently of water... Water pumps should be changed regularly. I do it every other season

good luck

jon

[chompin]

thank's jon
my case to is on the verge seting off the sensor
and when rpm gets slow the alarm go off