Testing Carburetor - Echo PB-251 Service Manual

PB-251

5-6 Testing carburetor

(B)
(A)
FUEL SYSTEM
1. Remove air cleaner cover. Push purge bulb sev-
eral times to fill and wet fuel pump circuit with fuel.
2. Pull off black fuel line (A) from carburetor and
connect pressure tester 897803-30133 (C) to fuel
inlet of carburetor.
3. Apply pressure to approx. 0.8 kgf/cm
The pressure should remain over 0.5 kgf/cm
4. If it drops below 0.5 kgf/cm
pump cover and repeat the previous Step 3. If it still
drops rapidly, proceed to Step 6 to locate the leak.
(C)
5. Apply pressure to 0.5 kgf/cm
purge bulb. Pressure should drop. If it does not drop,
check metering lever height for too low of a setting
(accorfing to "5-6 Checkihg metering lever"), or in-
let needle valve for sticking (according to "5-7
Checking inlet needle valve").
6. Remove fuel return line (B) and throttle rod from
carburetor, then remove carburetor from engine.
With pressure tester attached, submerge carbure-
tor in suitable clean solvent and apply 0.5 kgf/cm
(7 psi) pressure to locate the leak.
7. If the air bubbles come out between pump body
and carburetor body, check the pump diaphragm,
pump gasket, and diaphragm seat of carburetor
body. Refer to 5-5.
8. If air bubbles come out from carburetor bore,
check inlet valve, metering lever spring and meter-
ing lever height. Refer to 5-6 and 5-7.
31
2
(10 psi).
2
(7 psi).
2
(7 psi), re-tighten
2
(7 psi) and push
2