1970 60hp Johnson - main fuse problem

[needwarmth]

So I have a 1970 60 HP Johnson. I am blowing the main fuse after the motor runs for about 3-5 minutes. The fuse holder itself gets very hot before it blows. The ignition switch is good (just replaced). I have found a couple of "baked" wires that were probably grounded. I have fixed those. Still can't find the source of the fuse issue. The Hydro-Electric box was also checked and no broken or grounded wires can be seen. Does anyone have any ideas -very frustrating trying to narrow this down.

 

[freedon]

Re: 1970 60hp Johnson - main fuse problem

How is the engine cooling? I have a similar engine and was told that the most common thing to fail first when it overheats is the electrical system. Just a suggestion, best of luck!

 

[F_R]

Re: 1970 60hp Johnson - main fuse problem

Nobody can diagnose a problem like that from afar. You have to troubleshoot it on site. If you don't know how to check eletrical circuits, at least disconnect one purple wire at a time from the igniton switch. Hopefully, disconnecting one of them will result in the fuse not blowing. Then continue to isolate the problem within the circuit that is fed by that wire.

Another procedure is to insert an ammeter between the ignition switch and each purple wire, one at a time. The one that draws a lot of amps is the culprit.

Do you have the wiring diagram? Tracing circuitry without one is like driving across the state without a road map. Yeah, I know....GPS.