ignition switch key gets hot

[trbarret]

Hello all,

I am having a problem with my ignition switch key getting hot on a 1973 50 hp johnson electric start, the key and switch on the throttle control gets hot.

the motor has the charge loop system.

want to confirm my thoughts.

Sounds llike a corroded or high resistance connection in the throttle control box. I should be able to take the cover off and clean up the connections with fine sand paper and be good. i hope.

or is this normal?

any information would be helpful.

motor runs and starts easy, just don't want to burn up the switch.


thank you

Terry

 

[tashasdaddy]

Re: ignition switch key gets hot

sounds like you have a short. find it before a fire.

 

[glassmaster68]

Re: ignition switch key gets hot

can the switch get wore out inside and make a bad connecto?

 

[tashasdaddy]

Re: ignition switch key gets hot

yes, also those old wires, the insulation dries out, and falls off.

 

[Vic.S]

Re: ignition switch key gets hot

What ever, you have to sort it out.

TD may be right but I would have thought that if you had a short then you would already have had a fire!

My money would in fact be on a poor connection.

I would inspect the switch and the state of the wiring to it. If it is a poor connection then it will be pretty obvious where it is. It will be where the most damage to the insulation is occurring.

Push on connectors can be the cause of the trouble as can crimped connectors on cable ends.

Poor contacts inside the switch are also a possibility

Even if it is a poor connection you must sort it out before it gets worse and causes a fire.

 

[F_R]

Re: ignition switch key gets hot

What ever, you have to sort it out.

TD may be right but I would have thought that if you had a short then you would already have had a fire!

My money would in fact be on a poor connection.

I would inspect the switch and the state of the wiring to it. If it is a poor connection then it will be pretty obvious where it is. It will be where the most damage to the insulation is occurring.

Push on connectors can be the cause of the trouble as can crimped connectors on cable ends.

Poor contacts inside the switch are also a possibility

Even if it is a poor connection you must sort it out before it gets worse and causes a fire.

According to Ohm's Law, a poor connection (high resistance) would cause a reduction in current flowing through the circuit. A short (low resistance) to ground would cause a high current flow. It is high current that causes heat, not low current. In other words, you have a short or partial short to ground. It could be in the shift circuit, since that is the main thing the switch feeds. However, any wire shorted to ground will do it.

----OR----

A high resistance within the key switch itself could also be the culprit. The heat occurs wherever the point of resistance is. A light bulb has high resistance, that is why it gets white hot.

Why hasn't it blown the fuse?? That's what it is there for.

----OR-----

The shift circuit is fed by the alternator as well as by the key switch. If the alternator is not doing it's part, the load is increased across the key switch.

I think the problem is the key switch. But as you can see, it isn't an easy diagnosis without further testing.

 

[Black as]

Re: ignition switch key gets hot

I had the same problem a few years back, the safest way is to replace the switch and run new wires. Better to be safe than sorry.

 

[Silvertip]

Re: ignition switch key gets hot

The "A" (accessory) or "I" (ignition terminal on some switches) is incorrectly used to power lots of accessories. These terminals are intended to power the gauges and not heavy current draws. It is possible the accessories on this boat are being powered through this ciruit and the switch is just getting hot from the load it was not designed to carry. Has any rewiring or any wiring in general been done recently.

 

[trbarret]

Re: ignition switch key gets hot

no new wiring has been done, but the boat is old and if the connections in the shift box are corroded then that might explain why it's hot.

I will check it out in the morning, hoping it's just a corroded connection that can be cleaned up or replace the switch. I can use my meter to see what the resistance of the switch is.

thanks for all the ideas, i wanted to get some input before i open it up and see whats wrong, will keep u posted.


thanks
Terry

 

[ezeke]

Re: ignition switch key gets hot

If it were a short or an overload, it should have blown the 20 amp fuse at the engine.

It is more likely resistance from a poor connection, a failing ignition switch or a weakened wire.