1974 johnson 70hp control box getting warm

[Bob427]

what would cause my control box to be warm to the touch near the key and coke and cable side of the box

thanks Bob

 

[jtexas]

Re: 1974 johnson 70hp control box getting warm

exposure to direct sunlight for prolonged period of time? sorry couldn't resist.

There's keyswitch, neutral safety switch and overtemp warning horn in there. A direct short to ground would blow the fuse (20A fuse, inline fuse holder on the powerhead near the main wiring harness plug).

Is it warm all the time, or does it heat up just when the motor's running, or with the switch in the "on" position?

What accessories do you have that only get power when the keyswitch is "on"? The electric choke is one, what about tachometer or other gauges?

Is everything working ok?

 

[Bob427]

Re: 1974 johnson 70hp control box getting warm

no tach
over heat sensor
seems to only do it when the motors running



Bob

 

[ezeke]

Re: 1974 johnson 70hp control box getting warm

Heat in electrical wiring is caused by resistance. Could be overloaded circuit, wire is too small for accessories, wiring may be reduced to a few strands by wear or corrosion, or the ignition switch may be shorted internally.

Also, check the condition of the connections in the big red plug at the engine.

 

[Faztbullet]

Re: 1974 johnson 70hp control box getting warm

I have seen a defective horn do this also....

 

[Bob427]

Re: 1974 johnson 70hp control box getting warm

i will check out the wires

thanks Bob

 

[F_R]

Re: 1974 johnson 70hp control box getting warm

Heat in electrical wiring is caused by resistance. Could be overloaded circuit, wire is too small for accessories, wiring may be reduced to a few strands by wear or corrosion, or the ignition switch may be shorted internally.

Also, check the condition of the connections in the big red plug at the engine.

The second component of heat in electrical wiring is current. Once the motor is started and the choke is off, there should be no significant electrical current through the ignition switch. If there is, either you have something connected to it that shouldn't be, or there is a short circuit somewhere. Agreed the horn might be the culprit. The starter and choke are working ok, right?

It may be difficult for you to find if you have no basic electric circuit troubleshooting experience. But you can look for the obvious, like overheated (melted) wires, etc.

 

[Bob427]

Re: 1974 johnson 70hp control box getting warm

starter and choke working correctly
i am an electrician by trade
no melted wires no blown fuses
i have all my other stuff iscolated from the control box when not in use
and was not on when this happened

Bob