Taotao 125 broken carburetor?
 

Hello all. My son was riding his 125cc ATV and it shut off on him. He then had gas pouring out of the carburetor. I am not all that familiar with the inner working of ATV carburetors. Can someone help me identify the circled thing on the attached picture? There is gas pouring out of that thing, and out of the bottom of the air cleaner. Any idea on what might have broken? Is it fixable? If not can someone tell me what size carburetor to replace it with?

Thanks everyone!

Gday mb to me that looks like a air mixture screw .and for fuel to be leaking out of there the screw would almost have to be missing . that and leaking out the bottom of the filter would normally indicate that the fuel float or needle and seat are stuck

Welcome MB!

I think that is only a stud that has no particular use on this carb. I agree with Burge that the needle and seat are suspect.

That would make sense. The float being stuck would cause fuel to endlessly flow into the carb? I have not done carb work on an ATV. Does the whole carb come off and come apart to check the float or can you just drop the bowl and mess with the float?

Would that be similar to maybe the throttle getting stuck open at the carb? Basically something is stuck open that is just allowing gas to continue to flow constantly? I had to pull the fuel line off the carb and drain the tank before the gas would stop coming out of the carb. Come to think of it it was pouring out of what I would assume is an overflow tube as well. The tube that is connected to the bottom of the bowl.

On a side note, I was looking preemptively at aftermarket carbs in case I had to replace it. They are all based on a millimeter size. Is there something to measure that tells you what millimeter carb to buy?

Thanks all!!

this is how i learned


http://www.youtube.com/watch?v=cMVGO_sjL1Q

The China carbs are not measured correctly, AFAIK. I've installed several 30mm Mikuni carbs on 200CC and 230CC motors, and those have a 30mm cross-section at the choke opening. The proper way (if I understand correctly) is to measure the cross-section of the venturi opening, just prior to the throttle slide.

I'm pretty sure that your existing carb will measure 24-26mm at the choke opening, which is how to compare your carb with other China offerings. Try to buy the same size.

No, the throttle being stuck would not allow fuel to flow in a non-running engine. The throttle only controls airflow, and fuel will be pulled into the airstream as it rushes into the cylinder. The float valve is much like a toilet; when the bowl is full, the float closes the valve. Also like a toilet, the valve eventually wears out or gets debris stuck in it. Start by removing the entire carb and cleaning it thoroughly.

Thank you all!!! You guys are the best. I will pull the carb when I get home and see whats going on. I like having an idea what to expect before I just start tearing apart.

Thanks!!