To 30 starter wire getting hot

I've posted before about this issue. The starter wire
going from the battery to the starter switch on the
transmission housing is getting hot. The switch post
also gets hot. The thought is to change out the
switch. All connections have been cleaned good
twice. Today I noticed that the wire going from the
amp gauge to the starter switch is under the battery
cable wire on the switch. I'm going to change it
around and put the battery wire directly on the
switch post and the amp wire ontop of the battery
eye ring. Do you think it will make any difference in
the amount of contact and not get hot? Should I just
order the switch? Thanks,
 
It would appear that there is too much current.

Here's my logic:
The starter requires a certain amount of power to spin the engine. Using Ohm's law, P(power)=I(current) X E(voltage). If the voltage at the starter is lower than expected, the current rises. Current through resistance produces a voltage drop.

Perhaps there is resistance in the path causing the voltage to drop thereby increasing the current. The resistance is potentially in any connection - even the contacts of the switch. Ground plays an important part too. All ground connections should be clean and tight

I'd check the resistance across the switch terminals with the switch engaged. You can also check resistance from the battery positive to the starter connection with the starter switch engaged (battery disconnected). You could also check the voltage at the battery and then check the voltage at the starter while you are turning it over to see what the drop might be.

My personal hack method would be to use a screwdriver to short the switch terminals to see if the wire heats up. If not, the switch is resistive and likely needs replacing. If the wire still gets hot, there are issues with the starter or connections including battery cable gauge.
 
What's your starter doing while the cable/post are heating up? Is it cranking?

I went through something similar recently.
 
Tom it cranks slow even for a 6 volt. Occasionally it picks up speed to what I'd say is normal.
Graham, I know nothing about electricity. I do understand how to do the continuity check as you mentioned. What should the reading be when checked????? I see what you are saying by disconnecting the battery and going from the batteries terminal to the starter. Obviously I can read the numbers but would have no idea what they mean after I do the test. What should that read?
Since I kinda have planned to replace the switch if I cross the switch posts with a screwdriver as mentioned I would imagine it would turn over the starter at the proper speed if the switch is indeed bad. Is this correct? Thanks for your help, John
 
Heat = excessive resistance

Excessive resistance in your case would likely be Bad connection, bad switch, bad battery cable. Cable may look good but have internal corrosion. Also don't overlook corrosion in the cable connectors. If cable itself is getting hot back away from the switch connection I would definitely suspect it being a problem.
 
I think for the easiest for you would be to use the screwdriver to short the switch to eliminate that as a source of the problem.

Resistance should be very close to zero if you go the measurement route.
 
Do you know what size battery cables it has?

A common problem is substituting automotive cables. They are too small gauge. It needs size 0 or 00 to work with 6 volt. Those typically can only be bought from a truck/industrial supply, not Auto Zone or Oreileys.

Try taking the switch out, get it where you can see it clearly. Look at the threads where the cable attaches. Sometimes if the cable has been arcing, it will melt the threads, char the surface where the cable tightens. When tightening the nut, be sure the cable end is compressed tightly against the back of the switch, and will not move once tightened.

Also look at the contacts. They will have some arcing, that is normal. But there should not be excess material burned or melted away. When reinstalled, be sure the contacts close tightly when the start lever is pushed fully.

If you want to check the resistance, best done with a volt meter "UNDER LOAD". Put each lead on opposite posts of the switch, it should show battery voltage. Engage the starter as if normally cranking, and read the volt meter. If making a good connection, the meter will be near zero. Anything more than about 1 volt indicates a poor connection. You may have to reposition the leads to pinpoint the area of high resistance, but that is the only true way to find the resistance. Using an ohm meter does not apply a load, and will give a false good reading.

Moving the amp meter lead to the battery will not accomplish anything, as long as it is the right size terminal to fit the stud and does not interfere with getting a tight connection. I like to keep the battery free of small connections, as they are more prone to fail from corrosion, getting gnawed on by jumper cables, or misplaced in the dark.
 
Steve, thanks for the reply. I'll try the switch for resistance under load. Cable size is unknown but looks bigger than regular car size. Since I need to get it right some new parts have been in order for a little while now.
I'll get new wires, switch and report back. Thanks everyone.
 

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