How do we test the overheat warning horn?

[22trophy]

Hi Everyone,<br />I recently overheated my 99 Force 120HP outboard. My overheat warning horn went off, after keepng it, at full throttle for to long (not near max RPM either). Is there a way to test the overheat sensor?<br />Thanx<br />Engine compression checks good 150/150/150 and 145psi. No damage!

 

[RRitt]

Re: How do we test the overheat warning horn?

sounds like the sensor is working fine but either the impeller isn't working so good or the thermo isn't opening all the way when it should.<br /><br />my engine runs cool enough to touch. not touch comfortably mind you, but touch nonetheless. Like a hot car seat on a sunny summer day.

 

[imported_LakeRunner]

Re: How do we test the overheat warning horn?

Technically if the impeller was the problem, you would be experiencing this when the motor is at idle. The thermostat would be my first item to check off. Also you may want to back flush the motor. If you recently beached the boat or ran thru a sand bar, you could have debri in the line somewhere. It wouldn't bother low flow conditions but would starve the motor for cooling at higher rpms.

 

[lennygilbert]

Re: How do we test the overheat warning horn?

I test mine at least once a month.Take a long screwdriver and ground out the connection at the sensor.You should hear the buzzer go off.

 

[roscoe]

Re: How do we test the overheat warning horn?

1999 120hp recommended WOT rpm range is 4750-5250.<br /><br />What rpm's are you getting?<br /><br />If you are not at or above 5000rpm at full throttle, you need to reprop to get the rpm's up there.<br /><br />If you aren't even getting the 4750 minimum, repropping is a MUST, as you are lugging the engine if it is not capable of reaching these rpm's. Lugging can cause overheating, and more serious long term damage.<br /><br />Here, read this link:<br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000015

 

[roscoe]

Re: How do we test the overheat warning horn?

If you want to test the sensor, remove it.<br />Check for continuity, should be none.<br /><br />Immerse in hot water, 180*, switch should close and show continuity.

 

[22trophy]

Re: How do we test the overheat warning horn?

Thanx!!