Fuel Inlet

Fig. 2 Carburetor fuel bowl vent system:

Purpose
The fuel inlet system maintains a specified fuel level in the fuel bowl allowing the fuel metering system to deliver the correct air/fuel mixture to the engine.

Operation
The fuel inlet needle position is controlled by a float and lever assembly hinged on the float pin.
- The amount of fuel entering the bowl is regulated by the distance the inlet needle is moved off its seat.
- When the float drops, it causes the inlet needle to drop and this allows additional fuel to enter the bowl.
- As the fuel level reaches a specified level, the inlet needle is raised to a position that will allow only enough fuel to enter to replace that being used by the metering systems.

The float bowl uses a solenoid valve to operate the dual venting system, Fig 2.
- When the ignition is On, the bowl is vented internally to the air cleaner.
- This balances the bowl with carburetor inlet air.
- When the ignition is OFF, the bowl is vented externally, and fuel vapors are stored in the carbon canister to be drawn into the engine when the engine is started.