Flooding can be recognized by gas overflowing over the top of the carburetor, through the vents, or out of the throttle shaft.
Flooding can be caused by 1 or more reasons which are listed below in no particular order.
- A dirty carburetor is the most common cause of flooding.
- Dirt in the needle & seat may be holding the needle open. Try blowing some air into the inlet. This may dislodge any dirt. Test your needle & seat.
- The float may be leaking making it too heavy. Black Nitrophyl floats can absorb fuel over time. These have to be weighed as they are a solid float. 8.5, 9.5 grams for two of the Nitrophyl floats used on the 2150.
- Fuel pump pressure is too high. 4.5 lbs would be norm. If you happen to have an electric fuel pump you should add a regular between the fuel pump and the carburetor.
- The power valve might be allowing fuel through at low speeds. You should not be able to blow through the power valve in at least one direction. You can use a vacuum gauge to test providing you can come up with some kind of rubber to cover the valve.
Gas dribbling out of the venturi at idle, or when engine is off?
- This can be caused by plugged idle vents. These are the small passages leading from the idle mixture screws to the top of the carburetor.
- The venturi gasket may not be sitting flat and will need to be trimmed.