Why does the fuel petcock valve need to be turned?
More modern motorcycles have changed some of this in a few ways: the fuel petcock could be vacuum operated, closing with the engine off. the fuel tank could be lower than the carbs, making a fuel pump necessary.
What does the petcock do on an ATV?
The fuel valve, or fuel petcock, is a small shut-off valve that controls the flow of liquid fuel. ATVs and UTVs, like motorcycles, have fuel tanks that are situated higher than the carburetor and fuel feeds are controlled by gravity.
Why is my carburetor overflowing with fuel?
They use all sorts of tricks, holes cut into venturi, butterfly plates to restrict flow, secondary circuits to add enrichment to compensate for cold or reduce to compensate for heat, all sorts of things. The very, very best are really good at what they do for a limited range of temperature and altitude and RPM.
What happens if you don’t shut off the carburetor?
Without the shutoff, if the carburetor float failed to close the valve tightly enough to stop the fuel flow, then gas would continue to trickle into the carb, overflowing the bowl and flowing down into the intake tract. If the intake valve were open, it would fill the cylinder.
More modern motorcycles have changed some of this in a few ways: the fuel petcock could be vacuum operated, closing with the engine off. the fuel tank could be lower than the carbs, making a fuel pump necessary.
They use all sorts of tricks, holes cut into venturi, butterfly plates to restrict flow, secondary circuits to add enrichment to compensate for cold or reduce to compensate for heat, all sorts of things. The very, very best are really good at what they do for a limited range of temperature and altitude and RPM.
Without the shutoff, if the carburetor float failed to close the valve tightly enough to stop the fuel flow, then gas would continue to trickle into the carb, overflowing the bowl and flowing down into the intake tract. If the intake valve were open, it would fill the cylinder.
When does the fuel pump stop filling up?
Pumps are designed to automatically stop when air pressure changes are detected as the tank fills up. Should you continue to add fuel, it could simply dump it onto the ground through the overflow tube.