Hi, My son's coolster 110 atv will not start. When I pull on the brake handle, the taillight comes on and then hit the start button, the tail light goes out but nothing else happens. It comes back on once i release the start button. I've got a multimeter but not much experience on its use. Any suggestions on where to start looking?

Thanks,
Roy

 

Hi Roy,

Sounds like your battery is dead, but lets make sure:

1) Set your meter to the 20 volts DC scale. Place the red lead on the battery (+) post. Place the black lead on the battery (-) terminal. What voltage do you read? Hint: Be as exact as you can when reporting results - like "I got 11.9 volts", or "I got 12.4 volts". In contrast, vague statements like "it measured good" or "I got nothing" are not very helpful at all.

2) Turn on the ignition, set the brake, and try to start the quad. While the start button is being pushed (and the brake light has winked out as you reported before), measure the battery voltage as you did in 1) above. What voltage do you read now? Again be exact as you can. I'm yearning for information - the more information I have the more I can help.

If your battery voltage (measured right on the battery itself) collapses when the starter motor is engaged then the battery is either bad or discharged. Then we need to charge (or change) the battery, check the charging system, etc. That's one path...

If the battery maintains voltage while attempting to crank the starter then we need to look for bad connections, bad starter motor, etc. That's another path...

Life is not always black and white. Sometimes the battery voltage collapses somewhat, and it isn't a clear cut choice between the two extremes above. Exact readings are very helpful for navigating through these gray areas.

Lynn

 

Lynn,
Thanks for the detailed reply. Here are the details that you requested. The battery was reading 5.78 volts and collapsed to .20 volts when I engaged the starter button. The battery hadn't been holding a charge very well, so based on your reccomendation I'll replace it.

Thanks,
Roy

 

Yes, that is definately a bad battery since it is completely dead and won't recharge. But after you replace it you need to make the quad charging system is working, or it will be dead again in a couple weeks.

To test the charging system:

Start up the quad, turn off the headlights, and rev the engine up to a medium fast speed. Measure the battery voltage at the battery like you did before. It must be 13.5 to 14.5 volts DC. If it is your charging system is working. If it is reading down around 12.6 volts or less then you've got a charging system problem to solve before your quad is working.

 

Lynn,
It's been a while since you helped me with a battery issue but I think i have a charging issue as well. I just recently put in a new battery and the quad (110cc Coolster) was used off and on for about 10 hours before it wouldnt start. I charged it and the voltage came back up to 12.94 V. I started it and kept a meter on the battery terminals as i ran the engine at half throttle for a couple of minutes. The voltage came up slowly to 13.01 after 2 minutes of running. Some months back the stator was slightly damaged by a bolt that came loose inside the housing. I'm wondering if that is the problem. Let me know what you think.

 

My sons 3050 B seems to have weak charging output. At off idle RPMs the highest neasurable voltage at the battary is slightly less then thirteen volts. The voltage drops below twelve volts if the brake light is activated. does anyone have any suggestions or test procedure ideas? Thank you.