I have read every post on this site regarding this problem, but none of them are exactly like the problem I'm having. I have a 125cc Leopard Quad. Out of nowhere, it just won't start. I had just started it fine earlier that day, and now the solenoid just clicks. The battery is new, and I already tried jumping it with my car. When I jump the solenoid with a screwdriver it sparks, but nothing else happens. Lights etc work fine. New Carb. I tried banging on the starter with a screwdriver but got nothing.
There is 12 V coming from the battery, and I don't know where else to measure or what the measurements should be. I saw a picture of a plug that someone posted asking if they had a DC starter or something like that.
I think that it was a picture of a little box in the front behind the headlight
where wires go into and it's screwed onto the frame. Mine has wires connected with metal clips that are all connected. Not clips but the electrical connectors that are used on wires. Arghh I don't know how to explain them but they slide on and off of the clips on the plastic thing.

 

If you have 12 volts measured right at the starter motor, and it is not turning, then your starter is bad, or the engine is too hard to turn. The latter possibility is the extremley unlikeley since it was running fine last time.

But we're getting ahead of ourselves... Use your meter to measure the DC voltage right on your starter motor while you are cranking (or attempting to crank) the engine. Use the 20 volt DC scale. Red meter lead goes right on the starter motor input post, and the black lead goes to the starter motor case. Don't substitute measurement locations. Don't think like "It's too hard to probe the starter motor input post - I'll just probe at the starter solenoid instead. It's the same wire - I can see they are connected..." That would be totally wrong! You could have a bad connection between the starter motor and the solenoid, and miss this bad connection entirely in the modified test.

So let's find out if you have 12 volts at the starter motor (input post to starter motor case). While cranking (or attempting to crank) the starter what voltage do you measure?

 

All starter motors are DC. They run off batteries which are 12.6 volts DC. CDI's (which power the ignition system) can be AC powered or DC powered. CDI's have nothing to do with starter motors and cranking the engine. They have to do with generating spark which fire the gas/air mixture inside the engine after you get the starter motor to turn the engine. Perhaps this is what you are referring to? If so ignore it. Get the starter motor cranking first. Then once that is working we can go to other problems if any...

 

it measures 10v when I click the switch

 

12v at battery, 12 v at solenoid, then 10v at starter with the red side on the input and the black on the starter case.

 

Well I guess that solves it then. I now know that 10V is going into the starter, which is completely useless information to me.

 

Hmmm. I have to say that I think your impatience is both unwarranted and unrealistic. This forum isn't a help desk staffed 24/7 just for your benefit. Nobody here is paid. Everyone who helps here volunteers their time as a community service. But we have lives too, and family / friends come first. Waiting a day or two for a response isn't unreasonable .

10 volts is not an accurate enough reading. 10.0 volts is on the low side, and the starter could be stalling even under a normal engine load. 10.9 volts would be close to normal voltage for the starter motor. So if you could please be a little more accurate with those voltage readings (both at the starter and at the battery). Your meter must have more resolution than just 2 digits ...

When you attempt to crank the starter, you report the solenoid goes "click". There's voltage drop along the cable (how much is not known accurately enough yet). Hold the start button for 5 seconds then *quickly* feel all the connections from the battery through the solenoid to the starter motor, and all the fat ground wires from the starter motor back to the negative battery post. The wires/connections in this current path should be getting warm, but they should be getting *uniformly* warm along the wire lengths. And every connection should be the same degree of warm. A single connection that is hotter than the rest is a big red flag. Bad connections get *really hot* compared to similar connections when the starter draws current.

Another thing to try: Remove the spark plug and try to crank the starter. With no compression the engine should be a lot easier to turn. So if we were at the marginal point where the engine can't quite muster enough power to turn the engine over, then removing the plug should change things enough that the starter will turn the engine now. It's a data point - another clue...

If the starter motor doesn't tunr the engine with the plug removed then the next step is to remove the starter motor and see if the motor spins outside the engine. It could just be a shorted starter. Or pull off a side cover and use a wrench to see if the engine spins manually. A freely spinning engine would point back to the starter, or the starter clutch.

 

Thanks. I didn't mean to get impatient, I have just read and read and read and nothing I read seems to work. I know you aren't paid and I apologize. I am just so frustrated with this thing, I can usually figure out how to fix most things, and I can't
stand it when something beats me and I can't get it to work. I don't have a great meter. It's not even digital, it's the needle type, kind of like a battery tester. It's right at 10.0 though.

 

I understand frustration more than you know. We all face our own seemingly insurmountable problems - until they are solved. It is amazing how simple most problems become when looked at in retrospect...

I would consider buying a good meter. They are really inexpensive these days. It takes practice to learn how to use one to its full potential, but you'll be able to use this for many other things down the road.

Definitely do the "warm connection" tests, and pull the plug to see if the starter will turn the engine. These are important clues that help isolate the problem...