I have a moped talking, and on the carburetor there are usually two hoses, right? Because currently mine only has one coming from the carburetor, and the line is going to the gas tank. However, I do see on the bottom of the carburetor that there's another spot for a hose. Where is that hose supposed go?

I'm not sure - tell me if I'm wrong - but does it go to the intake manifold? And there's like an adjustment screw, which when I loosen, gas comes out and then I tighten it up and no gas comes out. Is it possible that there is supposed to be a hose running to the intake manifold from the bottom of my carburetor?


1 Answer 1


Your carburettor probably looks something like this:

enter image description here


This carburettor is what we call a float carburettor. Essentially, the bottom side of this carburettor works on the principle of a bowl, a float, and a needle. The bowl contains a certain amount of fuel to be drawn into the engine. Inside the bowl there is a float, which is attached to a needle. As the gas level goes up, the float raises the needle and stops the gas flow into the bowl. When the fuel starts to be consumed, the float drops, and allows more gas into the carb. Here's a good illustration of it:

enter image description here


According to the diagram at the top, the location you are talking about is simply a bowl drain. It is used when you are doing a carb cleaning, or, more frequently, a carb flush. I have personally used float bowl drains for emptying bad fuel or fuel with the wrong octane rating out of the carb so that I can have fresh going into the motor.

The hose is simply so that if you have to perform a carb drain, it doesn't drop the fuel on the hot engine.

TL;DR: Nothing's missing. If ever you do a carb drain, you might want to hook a tube onto that nozzle. Otherwise, it won't affect your engine at all.

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