Blowing Fuses

[2BoatinFools]

We've been working on our boat, it's a 1974 Fabuglass with an 1974 Evinrude motor on it. The problem we are having is that when we turn the ignition key, it's been blowing the fuse on the motor. Does anyone know what is wrong? Or does anyone know where we would be able to get a wiring diagram for it? It has the electric shifter in it, that has the push buttons for forward, neutral, and reverse. Any help would be greatly appreciated. Thanks.

 

[Joe Reeves]

Re: Blowing Fuses

Before removing the wires as follows, make a note as to what color wire goes to what lettered terminal on the switch.<br /><br />Remove all wires from the ignition switch except the 12v supply wire. Turn the key on. One by one, touch each wire to the terminal it was connected to. When you get to the wire that blows the fuse, tuen the key off and trace that wire to see where it goes. It's obvious that it is causing a dead short and the reason should be just as obvious once you find where it led to.

 

[Xcusme]

Re: Blowing Fuses

You might want to look at one of the blown fuses too for clues as to the reason for the blown fuse. If the fuse element is just melted in two, it usually indicates an over current condition. If the blown fuse element has a blackish tint, it indicates a dead short to ground.<br /><br />In the first case, too much current was drawn across the fuse and it melted. For example, 20 amp is drawn thru a 15 amp fuse. In the second case, a wire can be touching ground, resulting in a dead short. The full potential (amperage)of the battery tries to pass thru the wire (and fuse) which vaporises the fuse element producing the blackened blown fuse. <br /><br />As you know, never try increasing the size of the fuse to stop the fuses from blowing. If the fuse is too large, the wires become a fuse and can heat up to a point where they become toaster wires and start a fire. It always best to find the cause of the blown fuses. The fuses protect the wires from over currents.

 

[Hooty]

Re: Blowing Fuses

Here's a neat short locator courtesy of Schematic.<br /><br />"next time you troubleshoot a burnt fuse condition, simply use a headlight to act as a fuse. Install it where the fuse connects(use jumper leads). Start wiggling wires and turn on accessories until the light burns brite. You've then found the short, and no burnt fuses....."<br /><br />c/6<br /><br />Hooty