Testing Carburetor - Yamabiko ECHO SRM-420ES Service Manual

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4-6 Testing carburetor

C
D
F
FUEL SYSTEM
A
B
E
SRM-420ES, SRM-420TES
NOTE: To perform this test, carburetor interior
should be wet with fuel. If dry, a little leakage may
occur.
1. Remove air cleaner cover. Disconnect fuel line
(A) from carburetor.
2. Connect pressure tester 897803-30133 (B) to
carburetor fuel inlet.
3. Apply pressure approx. 100 kPa (1 kgf/cm
psi).
4. If pressure remains steady, follow step 5 and 6.
If pressure drops, proceed to step 7.
5. Lightly push purge bulb once. Pressure tester
reading should drop and remain above 50 kPa (0.5
2
kgf/cm ) (7 psi).
6. If reading does not drop, inspect inlet needle
valve for sticking or metering lever height is too
low.
7. If pressure drops at step 3, or if pressure drops
below standard fi gure at step 5, remove pulse pipe
(C) and purge line (D) from carburetor, then re-
move carburetor from the unit.
8. Submerge carburetor in suitable clean solvent to
locate the leak by applying pressure approx. 100
kPa (1 kgf/cm2) (14 psi).
9. If air bubbles come out between pump cover
and carburetor body (E), inspect pump diaphragm,
pump gasket, and diaphragm seat of carburetor
body (Refer to "4-10 Inspecting diaphragm and
others").
10. If air bubbles come out from throttle bore (F),
inspect inlet valve, metering lever spring, and me-
tering lever height (Refer to "4-9 Inspecting inlet
needle valve").
11. Reassemble removed parts.
NOTE: Replace carburetor gasket with new one
when remove carburetor.
T410S, B410S
T410TS, B410TS
2
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