How Does a Fuel Valve Work?
|Many honda mopeds
and scooters use a vacuum operated fuel supply valve. It is on the
of the tank, and has two hoses going to the carb. The larger one is the
gas line, the smaller is the vacuum line.
When the engine is running, the
vacuum line turns on the fuel valve, allowing fuel to flow into the
When you run out of gas, so there is none in the carb at all so the
will not run, and you add fuel to the fuel tank, you need to crank the
engine over about 15 seconds to allow the fuel valve to open long
to fill the carb and start the engine.
Many other brands use similar
valves on their mopeds, and many are located on the frame, separate
the fuel tank. Razz, Sundiro, most Chinese bikes, Suzuki FA 50, and
others use this type of valve.
To test the
valve, unhook the smaller (vacuum) line from the engine intake manifold
and suck on it. (apply vacuum). This operates the diaphragm in the
and fuel should flow out. If fuel always flows, even when the vacuum is
not applied, the valve may be stuck, or dirty.
Scooter Therapy Inc
12 North Few
Street | Madison,
1-608-255-1587 | E-mail
12 N. Few
9-6 Saturday, 10-3 CST