79 Evinrude 115 Overheating alarm

Runs great, no problems one day, next day alarm goes off after about and hour of running. I stop engine and restart to turn off alarm. Alarm stays off at low speeds until I up the throttle. Pee hole is fine, engine runs great. I had my mechanice check thermostate and impeller, everything just fine, runs in temp specs. I have also had carb rebuilt. I understand a solid alarm is either 1)overheating or 2)fuel flow. Could it be a faulty sensor? Should I just cut the tan heat sensor wire to the controls? Are there symptoms of reduced fuel flow? (It always is running great when the alarm goes off). Any help would be GREATLY appreciated.<br /><br />P.S. should I be running a 50:1 ratio with this engine? Thanks

Re: 79 Evinrude 115 Overheating alarm

You don't have a fuel flow sensor on that motor. I'd be very careful about assuming its running within temp specs unless I actually used some thermo-melt sticks or a some other accurate heat indicator. If you'rs sure its a bad sensor don't cut the wire, replace the sensor.<br />Yes 50:1 is the correct fuel/oil mix

Re: 79 Evinrude 115 Overheating alarm

Welcome to the forum!<br /><br />Constant horn is for overheat only. If you are running VOR a fast beep is no oil. But I dont think your engine has one.<br /><br />You can still have a blockage inside block and stoping water from circulating thru block. <br /><br />Tell tale stream is just a visual check to show water pump is picking up water. It does not mean water is circulating.<br />Water from tell tale does not go thru block or T..stat.<br /><br />You can check head temp. with melt sticks. you can getem from auto parts stores and some marine dealers.<br /><br />Should not run above 175 nor below 125.<br /><br />Yes you should be running 50:1 mix. One pint of twc-3 two cycle oil to six gallon 87 octane gas.<br /><br />Good luck!