So my ladyfriend's little brother got a 110cc Chinese ATV.
It stopped running so they brought it to a shop who put a new carb on it. It broke down again so I took a crack at it.

I drained out the 2 stroke mix and it ran much better. For a day. I drained out the gasoline again, from tank & carb.
Put fresh gas a bit of 2 stroke oil in it and it ran fine. Again, for a day. Started it up yesterday and spuddered.
If I crank it with the throttle wide open and then refire it, it will run for a few seconds then die.

What the hell is going on?

Thanks

 

My sons is doing the same thing. When it won't start I remove the float bowl and take out the smaller (idle) jet. Blow some carb cleaner through it and put all back to together. It then will run fine until the jet gets clogged again. I can remove the bowl without taking the carb off the atv. I'd see if you can see through the jets.

The odd thing on ours is that it ran fine all winter, now in the spring it's been acting up.

 

You have a two stroke engine on a china quad??

 

I would be double checking if its a 2 stroke, have a look at pictures of various chinese quad motors, namely the top of the engine known as the head, a 2 stroke will look different to a 4 stroke

 

That's the thing. The quad is definitely not a 2 stroke, there's no expansion chamber and it doesn't make the ying ying like a 2 stroke. I'm just dumbfounded.

 

If you are 100% sure this thing isn't a two stroke then quit putting 2 stroke oil in it. Also you may want to take the bowl off and clean the jets im not sure if the oil can clog them or not but it definetly sounds like a carb problem.

 

the oil in the mixture is coating all the carb with oil, and clogging all the moving parts, empty fuel from tank, clean the carb fully give the slow running jet a good clean, then do the same with the main jet, and dont forget the needle that is attached to the float. if this keeps sticking it wont let the fuel in to the bowl. then check the settings for the carb , ok.