A new battery did not fix our
ATV
starting problem.
We cleaned the solenoid and
tried starting it bypassed with a jumper cable.
The starter turned at that
point, but just barely...and the jumper got very hot after just a few
seconds. We think this indicates that the solenoid is bad and needs to
be replaced. Any gear head comments would be greatly appreciated if
you've got any experience with this troubleshooting procedure.
We used the multimeter to test the solenoid as well, putting the black prong on the negative terminal of the battery and the red prong on (in succession) each of the three solenoid posts. We got a 12 V reading from the post that attaches to the positive side of the battery, a 9 V reading from the smallest post, and nothing from the big post at the bottom (that I think goes to the starter?). Assuming I did it right (a big assumption), the internet seems to suggest this means the solenoid is bad?
(And the photo is when we were troubleshooting the breakers.)
A starter motor usually has the stator and the rotor wired in series. If the motor isn't turning, there is no back-EMF and the motor will draw a huge current resulting in lots of torque. Once the motor starts spinning, back-EMF slows the current and the torque drops off.
If the jumper cable gets hot, it means that a lot of current is going through. But if the starter hardly turns, my guess would be that the cross-section of jumper cable is way too small, giving too much resistance. Proper starter cables shouldn't get hot. Starter cables for a car should be rated for say 200 amps.
You can test the solenoid by setting your multimeter to resistance mode, touch it to the terminals of the power cables on the solenoid and operating the starter. If the solenoid works, the resistance should drop from infinite to almost zero when you hit the starter button.
DO not throw the meter in the ruts as was suggested- instead, get a good service manual and learn how to read a schematic and how a component works, then buy a quality meter (not a harbor freight POS) and learn how to use it.
Stabbing at things with jumper cables is a good way to fry some other, expensive component.
Jerry Freiman, Just for safety, its always better to have an inline fuse the same amperage rating as the wire, that way it blows the fuse before the wires get hot enough to melt or catch fire. What I would do if I were you (if money is know object) is buy a new aftermarket key switch, usually you can find them relatively cheap on ebay or amazon, that's assuming that the solenoid itself is fine then the new key switch should send current to the starter solenoid and bridge it completing the circuit like its supposed to.
I can tell you that the setup with 16 gauge wire with the push button will not work, that wire is too small, You could however use smaller wire and run a hot from the battery to a push button and then to the hot on the solenoid (not the posts with the heavy gauge cables, but where the harness connector connects to the solenoid) basically using the push button to engage the solenoid.
But replacing the Key Switch sounds the simplest and safest way.