Fuel Lines and Hoses
Fuel lines and
hoses carry fuel from the tank to the engine. The main fuel line allows the fuel pump to
draw fuel out of the tank. The fuel is pulled through this line to the pump and then to
the carburetor, or metering section of the injection system.
Fuel lines are
normally made of double wall steel tubing. For fire safety, a fuel line must be able to
withstand the constant and severe vibration produced by the engine and road surface. Lines
are placed away from exhaust pipes, mufflers, and manifolds, so that excessive heat will
not cause vapor lock. They are attached to the frame, the engine, and other units, so the
effects of vibration will be minimized. Fuel hoses, made of synthetic rubber, are used
where severe movement occurs between parts. A flexible hose can absorb movement without
breaking. Hose clamps are required to secure fuel hoses to the fuel lines or to metal
lines and hoses are a common source of fuel leaks. Fuel hoses can become hard and brittle
after being exposed to the engine heat and the elements. Engine oil can soften and swell
them. Always inspect hoses closely and replace any in poor condition. Metal fuel lines
rarely cause problems; however, they should be replaced if they become smashed, kinked,
rusted, or leaking. Remember these rules when working with fuel lines and hoses:
a rag around the fuel line fitting during removal. This action will keep fuel from
spraying on you or on a hot engine. Use a flare nut or tubing wrench on fuel line
only approved double wall steel tubing for fuel lines. never use copper or plastic
smooth bends when forming a new fuel line. Use a bending spring or bending tool.
double lap flares on the ends of fuel lines. A single lap flare is not approved for
fuel line hold-down clamps and brackets. If not properly supported, the fuel line can
vibrate and fail.
all fuel lines and hoses away from hot or moving parts. Double-check the clearance after
use approved synthetic rubber hoses in a fuel system. Vacuum hose is NOT to be used as
sure fuel hoses completely cover its fitting or line before installing clamps. Pressure in
the fuel system could force the hose off if not installed properly.
all fitting for leaks. Start the engine and inspect the connections closely.
Most fuel injection systems have
very high fuel pressure. Follow recommended procedures for bleeding or releasing pressure
before disconnecting a fuel line or fitting. This action will prevent fuel spray from
possibly causing injury or a fire.