I went to run my boat that has a evinrude 115 and as soon as i turn key to start the alarm would sound off.?

Question

I was going to start up boat in the driveway for first time this year to make sure everything was working and shortly after it started it the alarm went off. I went back to see if the motor was peeing. The water pump seems to be working fine because I have a strong stream of water coming out and the water pump and thermostat are only two years old. There is no oil injection and the motor only has 50 hrs since it was rebuilt. Any ideas would help thanks

Answer 1

Since you say there is no oil injection,the only other system that the horn runs is temperature.Maybe the overheat sensors

in your cylinder heads are not working properly?This is the only thing I can think of that would sound your horn.Hope this helps.

Answer 2

Disconnect the temp sensors one at a time and try it. If alarm still sounds with both disconnected, then you will have one of those wires shorted to ground, or I have found two horns loose in the control box which were shorting to gound. The horn itself is isolated by its plastic holder. It can "wiggle loose" and touch the casing causing a short.

Repair, don't defeat the temp warning system. You'll be sorry if you do!

Answer 3

How shortly after starting?  Age of thermostats is irrelevant.  Overboard water indicator only tells you the pump is pumping, it doesn't indicate whether water is circulating the powerhead.

General rule, if you can't hold your fingers on top of the cylinder head for several seconds without permanent scars, it's too hot.

The temp switches can be tested in a pot of water on the stove with a kitchen thermometer, using a multimeter or test light & 12V power source.  Switch should close at around 165º F.

Cylinder head temp can be measured with an infrared temp gun, or thermomelt sticks.