Sunl 90 Automatic ATV.. Bought it (used) a year ago for my 4 year olds birthday...
Ran great, all remote functions worked.. Typical battery drain after a couple of days of not running, but accepted and dealt with that issue by keeping it charged..

Winter time came, and he didn't ride it for a while.. Even though it has a manual fuel valve, apparently some fuel got left in the carb bowl and gummed things up..

Went last week to get it going again. I pulled the carb, cleaned the main jet and sure enough the needle was stuck in the jet.. Got it all cleaned up and freed up..

Reassembled the carb and quad.. Got fire, got fuel, bike starts.. , revs fine, runs fine, etc...
BUT IT WON'T SHUT OFF !!!
Remote control won't shut it off, keyed ignition switch won't shut it off, handlebar switch won't shut it off..
The only way to shut it off is to turn the fuel off (which takes a while to burn out) or pull the choke and "bog" it down and kill it..

Can you offer any suggestions ?

My boy is pretty well versed on riding the quad safely.. With the governor in place, I'm not required to use the remote kill switch..

Is removing all electronics except handlebar switches (on-off, and start), and charging system, and headlight an option? Basically get rid of the remote functions, alarm, tether switch, brake safety switch, etc..

Wire it up just to start, run, and shut off?

Thanks in advance for any direction you may be able to give me..

signed,
frustrated father of impatient four year old..

 

Sounds like you may be missing a ground, without a ground to dump the ignition pulse to, nothing short of running out of gas will stop it, you must have a loose,corroded,or broken wire to the frame or from the ignition to ground. Try tracing the wires from the key switch, one should be hot, another go to the cdi/coil, and one should be a ground to short out the signal to the ignition to kill the motor. If it has a kill button/switch, even better, that should go right to ground, sounds like all yours must go to a common wire, and that one wire is not grounding, so it won't shut off.

 

Does you CDI look like this?
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If so, the way the quad is shut off is to ground the kill switch pin. There are up to four kill switches on the quad:

1) The left handle bar kill switch
2) One pole of the two pole ignition switch
3) The remote control module
4) A tether pull cord kill switch

All the kill switches are wired in parallel - that means that any one of them could short the kill switch wire to ground and kill the engine.

So you could have a missing ground (as 95wolv already said), but this missing ground would have to be missing to just *some* of the circuitry since the quad starts and runs. For example the CDI must be getting a ground or it wouldn't run at all. So along this train of thought do you notice anything else that doesn't work? Headlights, battery charging circuitry, etc? If yes then missing grounds is a likely possibility.

Another likely possibility is the kill switch wire to the CDI itself. All of the other kill switches wire to that very point. If you have a bad connection or a broken wire here you will get exactly the syptoms you described - i.e. none of the kill switches work. Look very carefully at the kill switch pin at the CDI. Wiggle the wire. Does the connector pin seem like it isn't grabbing the mating pin on the CDI?

Try grounding this wire with an alligator jumper wire from engine ground to/through a small screwdriver shank probing into the CDI connector kill switch pin. Does shorting that pin to ground kill the engine?

Be Careful...

The kill switch pin could have high voltage on it whenever the engine is turning. Whenever you probe this wire make sure your fingers are not part of the circuit. It can knock you on your butt, so make sure you are only holding the insulated screwdriver handle when doing this...