I have read that it is good to drain all the fuel out of your carburetor if you will not be riding the quad for a long while. The article suggested turning the fuel off while the motor is running to drain the fuel out of the carburetor. I tried this on my quad which has a modified 350X motor. When I turned the fuel petcock off, the motor gradually started reving higher and higher until I had to pull the kill switch. I expected it to just stall when the gas quit flowing, but it goes lean and starts reving higher. This happened once while riding when I started running out of gas. Does anyone know why the motor would not just stall like when my lawnmower, car, or street bike does when they run out of gas? The petcock does shut the gas completely off beause I have pulled the fuel line to make sure. Any insight would be appreciated. Thanks.

 

What probably happened is that the lack of fuel and abundance of air going into the engine made it rev like that. When the carb is running out of gas the fuel/air mixture has a high content of air and not a lot of fuel. The air makes the thing start revving really fast. The same thing happens if you have an air leak, it will start to suck a lot of air and then it will rev to the moon. With an air leak you can kill the engine and it still runs because of the extreme heat. This is not a good thing. The next time you try to run the gas out of the carb, listen to the engine and as as soon as the idle starts to speed up kill the engine. This is the best way to get all the gas out of the carb and it won't hurt anything.