I bought a used Chinese ATV 150cc (can't tell who manufactured it). It would only start if you short the solenoid while pressing the red start button or kick start it (too difficult from by 13 year old). I read somewhere that my solenoid was bad so replaced it. Next the batters seemed to be dead. I tried jump starting the ATV but as soon as I connected the jumper cables the starter motor engages. The safety wires at the back of the ATV are cut and it looks like the previous owner was using the broken solenoid as the start switch. Any ideas what to look for in the wiring that was modified to bypass the start switch? I also disconnected the start switch wires but when the battery is connected the starter motor engages. Kick starting without the battery works so mechanically everything is ok but electronically we are having issues.

Info:
1 black wire from the battery negative to the chassy.
1 red wire from the battery positive to the solenoid.
1 red wire from the the starter motor to the solenoid.
1 small read wire from ? to the solenoid (no idea what this is for)?
2 wire connector from the solenoid to starter switch (haven't traced it all the way back to the switch)?

 

On your solenoid find a small two wire connector at the end of two pigtail wires that runs into the wiring harness. Unplug that connector. Then hook up the battery (or jump it to another battery like you car). Does the starter still turn?

If yes, then your solenoid is bad, or the wires bolted to the two screw studs on the solenoid (one to battery, one to starter motor) are shorted together. Look for the shorted wires, else replace the solenoid.

If no, then there are problems with the wiring driving the solenoid.

The solenoid is a simple device. It is just a switch that shorts those two big screw terminals together, connecting your battery to the starter making it turn. You can short those terminals together manually with a screwdriver and do the same thing. The solenoid works by applying 12 volts across the 2 small wires going to the connector coming off the solenoid. The wires go to a coil which generates a magnetic field, which sucks down a steel plate, which shorts those two screw posts together - just like you did before with the screwdriver. So why use a solenoid? Because you can then use a little switch (start button) to switch on/off a little bit of current, which drives another switch (your solenoid) which then switches on or off a *lot* of current through big heavy wires.

I'm not understanding this. What safety wires are you referring to at the back of the ATV? How would you use a broken solenoid as a start switch?

Yes, I agree this is an electrical issue.

Lets get the starter motor to be still when the jumper cables are hooked up. Then get the starter to turn on command when the solenoid is shorted manually with a screwdriver. Then make the starter motor crank on comand with the start button.

 

Lynn thanks! My testing indicates that the new solenoid I purchased online is either bad or not the correct part. I unhooked the control wires from the solenoid and the starter motor still engages when I connect the battery. The old solenoid has 12V hand written on it and the new solenoid has ZTXF0910. I am guessing 10 is the voltage? If my ATV requires a 12V solenoid and I got a 10V solenoid would that cause the behavior I observed? Can anyone recommend a good place to buy a replacement solenoid online or locally (I live in Austin TX). The online store (RedCatOnline.com) I bought the solenoid did not show any part numbers just a picture and the ATV cc range of the solenoid.

1 x Starter Relay Solenoid for Chinese Engines *MOST-POPULAR* (SR299-21)

Lynn again BIG THANKS for you help!

 

I don't know anything about your particular posted solenoid number, but in general quad solenoids are such simple devices that for quads one size fits all electrically, as long as the driving coil (the small wires) has two wires instead of just one. There could be mechanical issues (it has to fit on the quad), and other issues such as the solenoid having a built in fuse feeding the rest of the quad, etc. But you would see that difference just by looking.

I don't think there is such a thing as a 10 volt quad solenoid. Batteries are 12 volts, so any quad solenoid will run on that.

I've seen lots of quad solenoids on eBay. There are probably many other reputable online places as well. Just look for a solenoid for chinese quads with two wires feeding the device, and two big lugs to attach your battery/starter cables. And make sure the mounting holes will allow attaching it to your quad.

 

Lynn is correct
there is not 10v solenoid. just had a problem with one last week that the wiring harness was wrong from factory. on the two wire connector check with a test light check the following, yellow/red should be hot when the starter button is pushed and then hook your test light to the positive on your batter and check the other wire (green i believe) to make sure it lights up for a ground.
do this with the solenoid unplugged and see what you get. your problem could be further up the line.