Small Engine Troubleshooting Problems? Ask a Mechanic Now.
What is the engine model number? Single cylinder engine or twin engine? Fuel mixture is usually not adjustable, and the needle valve only controls fuel into the float bowl. Mix is controlled by the size of the main jet.
Then I would rebuild or replace the carburetor. Be sure and check the float, as it ,may not be floating!
Float and the needle valve have to regulate flow of fuel into the bowl. If the float or needle is damaged , it can let excessive fuel reach the cylinder.
Sure, remove the bowl, the float will have a pin that hods it in place, remove the pin, and the float and needle will come out.
It can be stuck, use a screwdriver and lightly tap on the pin to see if it will move and then be pulled out with pliers. It should be a straight pin, and can go either direction.
See figure 6 for needle and float. Your carb will be similar design.
It has to have a needle!
Needle is in the passage from the fuel inlet, and is opened and closed by the float.
Will float , float in water? Could it be filled with fluid?
Yes, works best if carburetor is off and you hold it upside down!
Did you blow out the inlet passage, from needle side to fuel inlet side, with the fuel hose off, to clear any debris that may have been keeping needle open?
Sounds like the needle is not sealing the passage, either debris under the needle or bad needle, or the float is not pushing the needle into the passage.