just picked up this 110 ATV for my kids the other day. The guy I got it from so there’s a parasitic electrical drain somewhere so the battery dies in between rides. It can be started just fine with a booster box. First time I ran it it went for about 15 to 20 minutes, but then after I filled the tank with gas, it will go for 5 to 10 minutes and then shuts itself off. There is a vent hole on top of the gas cap and it will spew some gas when giving it full throttle. Would it hurt to open this hole up a little bit and put a hose on it so it doesn’t spray kids?

next question, do these require any voltage to continue running once they are started? I’m pretty sure the battery is completely shot because when I try to put a charger on it, it only shows zero or 1% charge after 30 minutes. I don’t mind to use my booster box, when starting because then I know the kids can’t go out and start it themselves

 

Most of those quads have AC ignition which is totally separate from the battery, a single AC coil feeds power to the CDI and a trigger coil on the outside of the flywheel tells it when to fire. There are some DC CDIs and they use the battery for power, though these too use a trigger coil for spark timing.

If you can catch it with the fault on, check for a spark. If there is no spark you have an ignition problem when hot. These are pigs to trace as the fault has often gone off by the time you can check components for faults. The most common faults are power and trigger coils on the stator as they get hot from the engine, but CDIs and ignition coils do warm up in use so could be the culprits. If your machine does have a battery drain, it is usually the rectifier. Check with a high ampage ammeter between battery and terminal, with ignition switch off, if the drain goes away when you disconnect the rectifier, it is faulty. When new, most filler caps have a vent tube which goes over a bit of plastic sticking up from the cap.