MTFCA Forum

I am working on a 26 that will start but turns over pretty slow but the starter will only drag if tried again a second time and the starter switch gets red hot. The cable to the battery gets hot also. I cleaned all the connections, same thing. The starter does not feel hot. Bad starter? Art

It could be a starter problem, but it could be the switch or the connections to the switch. If the starter switch gets very hot it is probably damaged. If the cables are the correct size, they should not get hot, and the switch should not get hot. NOTE: The starter is not designed to operate for more than about 10 seconds at a time. Grinding on it will overheat it, and will over-strain the battery. If the engine does not start in about ten seconds of cranking or less, stop cranking and let the starter cool down while you determine why the engine won't start. For the starting system to work as it should, all the parts, including cables, switch, battery, starter, and all ground points must be in good condition. The battery must be of adequate size and in good condition and fully charged. The engine needs to be in a good state of tune so that it will start readily, and the generator needs to be working as it should to keep the battery in a good state of charge.

The starter can get hot internally and still be cool to the touch on the outside. The starter should not be operated continuously for more than 10 seconds at a time without letting it rest for a minute or so before trying again.

If the timing is advanced too far when cranking the engine, the engine can fire against the starter. An easy way to check for this is to crank the engine with the ignition key off. If it cranks faster, the timing needs to be retarded more while cranking.

Are you using the proper size 6 volt battery cables?.... Just by looking, they are a thicker diameter than conventional 12-volt battery cables.

Does the cable from the starter switch to the starter get hot as well? If it does, then the problem is likely in the starter. If not, then the issue is maybe within the switch itself.

Do you know if the starter has ever been gone through? That could be the issue. Original starters and original radiators wear out after nearly 100 years. From what you’re saying it sounds more like the starter than the starter switch.

Original or repop type replacement switch? Repops regularly fail/burn out.
From what i have seen failures are a matter of when.
Originals can be easily refurbished if the bus bar is fairly solid.

When considering battery/starter cable size, one needs to know maximum amperage and length of the cable.

From a reliable model T source: 6 volt starting amperage may well exceed 250 amps and maybe as high as 300amps. For 12 volt systems cut those amperages in half.

Remember, KEEP the cable length as SHORT as practicable. Longer cable will need to be a larger size.
Remember, the LOWER THE NUMBER means LARGER cable AND HIGHER the number means the cable will be smaller.
There are many color coded graphs that coordinate amperage, length, and size. Google it.
ALWAYS use larger cable than you think you will need. The added safety margin just may make a BIG difference when you need it most.

Hi Art,
Try doing a volt drop test to isolate the issue. You will need help with someone to push the switch. Set your multimeter to DC volts & test along
the circuit. Battery to cable, cable to switch, across the switch, switch to starter. When you put the test leads on each section you will get no
volts until the switch is pushed. If you get more than a few tenths of a volt when cranking then you have resistance in that part of the circuit.
If you get several volts then you have high resistance in that part of the circuit. Resistance x volts & amps + heat.
Craig.

Try a jump test between the 2 starter switch terminals. (Heavy cable or jumper cable)
That will rule in/out the switch & starter.

I was just posting that. Lol

Try a jump test between the 2 starter switch terminals. (Heavy cable or jumper cable)
That will rule in/out the switch & starter.
A hot switch tells me insulators grounding or a bad internal connection.