Warning buzzer comes on after warming up

[kazumi]

Hi,<br />I'm glad that I have found a forum on outboard engines. I have a 1982 90 hp Evinrude.<br />The problem I am experiencing is starting to confuse me. While idling thru the boat harbor (2 to 5 minutes) the buzzer is fine, however soon as I throttle up (1 to 3 minutes) the buzzer sounds. However, after I checked to see if the engine was overheating (took cover off to touch the heads,it was only warm) the engine started up and ran fine the rest of the day, no buzzing sound. Changed the thermostat to no avail, same thing happened What should I do next. Kazumi

 

[Franki]

Re: Warning buzzer comes on after warming up

Sometimes engines get hotter at idle then they do at WOT.. it has to do with how efficient the cooling system is.. at low rpm, there is nowhere near the volume of water going through the system.. so the engine warms up, and then you flatten it,, maybe it takes a while to cool back down? dunno, just guessing really.. when did you last change the impeller?<br /><br />Perhaps you should do like alot of us did and add an external temp guage.. very handy.. search the archives if you wanna know how we did it...<br /><br />Also, if you want to check your temp sensor.. look for a brown or tan wire running from one of your heads.. (cyl 3 on a V4 I think) check the connection that is about 3 inches along, if that has lost its insulation and is touching earch, thats the sort of behaviour you'd get.. as a test, turn on your ignition and and touch the brown wire to earth, your horn should sound..<br /><br />hope thats of some help..<br /><br />rgds<br /><br />Frank

 

[petryshyn]

Re: Warning buzzer comes on after warming up

kazumi<br /><br />The buzzer can buzz in different ways meaning different things.<br />How does it buz?<br /><br />every 20 seconds = Oil level down <br />every other second = Oil Restriction<br />constant buzz = overheat

 

[seahorse5]

Re: Warning buzzer comes on after warming up

When you replaced the thermostats, did you use the stainless steel Evinrude ones, or aftermarket brass ones? Did you check the rubber seals and the white plastic pressure relief valves for sticking? Was the air bleed hole unrestricted?<br /><br />If the water pump is OK and is the correct one, sometimes overheat problems can be caused by salt buildup in the cylinder heads under the cover plates. Rubber water deflectors in the cylinders, accessable after the head is removed, can melt or distort, giving strange overheat symptoms. Get a proper service manual for pictures and a more thorough explanation.