[johnny centineo]

The cooling alarm on my 150 Evinrude outboard is sounding. All water ports appear to be working fine. Any ideas what could be causing this?
Thanks

[ezeke]

Alarms are for different reasons on different years so it is important to tell us the year, or the model number so that we can look it up.

A constant alarm is generally caused by an overheating condition, but can be a fuel obstruction on many V6 models.

[Chris1956]

Johnny, The thermostats could be shot, the water pump could be weak, the temp senders could be faulty, the wiring could be bad.

Put your hand on the head and see if it is too hot to touch. That will narrow it down. If it is hot, it is thermostats or pump.

[johnny centineo]

Thanks for the responses. It is a 78 year model. all water ports show a storng water flow. I noticed steam on the lower unit and it ecame hot to the touch.

[walleyehed]

If it hasn't had a pump and housing in the last 3-4yrs, I'd do it now....
On the cyl. head there are possibly 2 temp senders that go through a molded "ring" in the head casting...they are rubber (in the head) with a single Tan, I believe, wire coming out of the center....follow the wire from the sender and there should be a connector you can take apart. Take the wire end that goes forward and touch it to a ground on the engine with the key on....it should sound the alarm.

Does the alarm sound after a few minutes of running?? 30 minutes?? at idle? wide open throttle?

[emdsapmgr]

The thermostats are set to open at 143 degrees, which will mean the engine should idle around 145 or slightly higher.The temp switches in each head will sound the horn if either gets up to 212 degrees. It will shut off when that head gets back down to 175. You have an overheat if you are getting steam. Could be that one of the two thermostats is stuck shut. If you have not ever done any cooling system maintenance, I'd feel safer if the impeller was replaced. Also, I'd take the two thermostat housings apart and replace the thermostats and check the pressure relief valves for overheat deformation.

[johnny centineo]

Thansk again everyone.

As to the alarm, it sounds when you start the engine and even when the engine is cold.

[HighTrim]

Remove the tan temp wire from the horn, if the beeping continues, the horn is faulty.

If the horn's beeping stops, one of your components is at fault here. Disconnect the tan wire from the sensor that was mentioned and see if the beeping stops, if it does, the sensor is to blame.

NOTE: Just because the sensor or horn is to blame, that is not to say that you do not also have an overheat problem. Maintain that water pump/impeller as stated.

[johnny centineo]

Thanks and will do.