Echo CS-310, Service Manual

Page: 35 / 75

FUEL SYSTEM
CS-310
33
4-9 Testing carburetor
NOTE: To perform this test, carburetor interior
should be wet with fuel. If dry, a little leakage may
occur from diaphragms and/or inlet needle seat.
1. Remove cylinder cover, air filter and cleaner
case. Disconnect fuel line from carburetor. Connect
pressure tester 897803-30133 (A) to carburetor
fuel inlet.
2. Apply pressure approx. 98 kPa (1 kgf/cm
2
) (14
psi).
3. If pressure remains steady, follow step 4 and 5.
If pressure drops, proceed to step 6.
4. Pull starter grip. Pressure tester reading should
drop and remain above 49 kPa (0.5 kgf/cm
2
) (7
psi).
5. If reading does not drop, inspect inlet needle
valve for sticking or metering lever height is too
low.
6. If pressure drops at step 2, or if pressure drops
below standard
fi gure at step 4, remove carburetor
from the unit, disconnecting purge line, throttle rod
and choke rod.
7. Submerge carburetor in suitable clean solvent
to locate the leak by applying pressure approx. 98
kPa (1 kgf/cm
2
) (14 psi).
8. If air bubbles come out between pump cover
and carburetor body (B), inspect pump diaphragm,
pump gasket, and diaphragm seat of carburetor
body (Refer to “4-13 Inspecting diaphragm”).
9. If air bubbles come out from throttle bore (C),
inspect inlet valve, metering lever spring, and me-
tering lever height (Refer to “4-12 Inspecting inlet
needle valve”).
A
B
C