Carburetor fuel bowl vent control

Claim 1

A fuel bowl rollover anti-spill device for use in a carburetor having a float bowl and a cover closing the float bowl, the bowl containing liquid and vaporous fuel and a fuel vapor space above the fuel, an atmospheric air passage connected at one end to the cover, the cover having a hole therethrough connecting the vapor space to the air passage for the venting of fuel vapors into the air passage, a valve movably mounted in the air passage adjacent the hole for movement to a first position into the hole to close the hole and for movement to a second position out of the hole to open the hole, first means to move the valve to the second position out of the hole to permit venting of fuel vapors from the space into the passage when the carburetor and fuel bowl are in a normal attitude, and second means to move the valve to the first position into the hole to close the hole and seal against any leakage of fuel from the bowl into the atmosphere through the cover when the carburetor and fuel bowl attain an attitude permitting fuel to flow to the hole, the second means including spring means acting on the valve biasing the valve in a direction towards the first position to close the hole, the first means including vacuum means acting on the valve to move it to the second position opening the hole in response to engine running operation to permit venting of the fuel vapor through the hole into the air passage.