Carb Flooding

Carburetor Flooding

(Excessive Fuel at Idle)


If your engine is acting like it is too rich at idle:

1)      Excessive black smoke

2)      Fouled and sooty spark plugs

3)      Idle mixture screw all the way in and still too rich

We suggest the following checks for diagnosing the root cause:

1)      Remove air cleaner and observe for fuel dripping into engine

2)      Check fuel pressure. (Normal pressure is 4-6 psi)

3)      Run fuel line into clear container and visual for foreign material.

Flooding is usually (99%) caused by dirt in the needle & seat and it will be necessary to remove the carburetor top and wipe it clean and inspect with a magnifying glass for debris trapped or embedded in the needle. NOTE: Never use Teflon tape for the fuel inlet fitting. All carbs sold by us are checked to hold pressure to 10 psi. Dirt in the fuel system is often loosened by today’s ethanol in our gasoline. The ethanol is also responsible for premature deterioration of the diaphragm in the fuel pump. A modern paper element type fuel filter* is mandatory for adequate filtration. Your new fuel line must be flushed to eliminate any possibility of debris (caused by fuel line fabrication) getting into the carb.

The float could be defective – however we have not seen on in several hundred carburetors.**

We will test and clean any returned carbs at our expense, but customer assumes expense of shipping.


*Located between the fuel pump and the carburetor.

** Float level readjustment is usually not effective in resolving flooding. Smaller jets will never have any effect on this issue.