Suzuki FU150SC Manual page 47

4-1 FUEL AND LUBRICATION SYSTEM
FUEL SYSTEM
When starting the engine, a negative pressure (vacuum) is generated at the intake port. This negative
pressure draws on the fuel valve diaphragm, (through a passage way in the carburetor intake pipe) and
vacuum hose. Due to this, the negative pressure increases behind the fuel valve diaphragm, until it is higher
than the valve spring pressure. The valve in the fuel valve is then forced to open (due to this diaphragm
operation) and allows fuel to flow into the carburetor float chamber.
<=) _:«Negetive pressure
<mt Fue!
FUEL AND LUBRICATION SYSTEM 4-2
AAWARNING
Gasoline is very explosive. Extreme care must be taken.