Checking Fuel Tank And Tank Vent - Echo PB-251 Service Manual

27
PB-251 FUEL SYSTEM

5-3 Checking fuel tank and tank vent

1. Disconnect black fuel line from carburetor and
(B) connect pressure tester 897803-30133 to fuel line
by joint pipe V186-000020 (A).
(A)
2. Pinch tank vent line (B) with longnose pliers to
2
block air passage. And then apply 0.5 kgf/cm (7
psi) of pressure.
NOTE: Wrap the ends of longnose pliers with tape
(or cover with soft pipes as shown) to prevent dam-
age to tank vent line.
3. The pressure should not drop. If the pressure
drops, leakage may be occurring from fuel cap
gasket, fuel tank, fuel lines, tank vent line or grom-
mets. Check and replace them as required.
4. Release tank vent line. The pressure should stay
2
at or above 0.1 kgf/cm (1.5 psi). If pressure drops
2
under 0.1 kgf/cm (1.5 psi), tank vent or tank vent
line is defective.
(D)
NOTE: Tank vent prevents a vacuum from forming
in fuel tank when fuel in fuel tank is being consumed.
When pressure in fuel tank becomes too high, tank
vent releases the pressure.
5. Remove tank vent (D) from tank vent line and
connect pressure tester.
2
6. Apply pressure approximately 0.5 kgf/cm (7 psi),
make it sure the pressure should be stable in range
2
of 0.1 - 0.4 kgf/cm (1.4 - 6 psi).
7. If it is not in the range, gently clean tank vent with
compressed air or replace with new one.
(E)
(F)
NOTE: Do not disassemble valves in tank vent as-
sembly. Damage to valves will occur.
(G)
8. Remove cap (E) of tank vent, and clean sponge
(F).
(H)
9. Cut pipe 363024-04010 (G: 7x11x170mm) and
(J)
382011-01110 (H: 9x13x350) in approximately
30mm (1 1/4 in) length, and connect them to
pressure tester as shown. Connect tank vent (J)
without cap to pipe as shown.
10. Plug hole ( j ) by finger and apply pressure 0.2
2
kgf/cm (3 psi). The pressure should be hold steady.
11. When the finger is removed from hole ( j ), tank
( j )
vent should pass air freely without holding any
pressure. If it does not, replace tank vent with new
one.