Checking Diaphragm And Others; Removing Main Jet - Bosch PB-650 Service Manual

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4-9 Checking diaphragm and others

(G)
(C)
(B)
(A)
(F)
(E)
2K463

4-10 Removing main jet

2K375
FUEL SYSTEM
(H)
(D)
(A)
(B)
1. Check metering diaphragm (A) for hardening, dis-
tortion, or pin hole. Replace it as required.
2. Remove pump body assembly (B) and pump dia-
phragm (C).
3. Check pump diaphragm, and replace it if hard-
ened or curled at the valve tabs.
4. Check metering and pump gaskets, and replace
if defective.
5. Check inlet screen (D) if blocked with dust. Re-
move and clean it, or replace it if defective.
6. Check purge bulb (E) for crack or fatigue. Re-
place it as required.
7. Check the slit of check valve (F) if deformed or
resinous. Replace it as required.
8. Check main jet (G) if clogged. Replace it as re-
quired, referring to "4-10 removing main jet".
9. Check O-ring (H) for crack or fatigue. Replace it
as required.
10. Clean the fuel passages in carburetor body with
gentle compressed air.
1. Carefully pry main jet (A) from carburetor with a
small screwdriver.
2. Inspect O-ring (B) under main jet and replace if
necessary.
3. Clean the fuel passage of carburetor body.
4. Clean main jet or replace it.
PB-650
PB-750
(PB-650)
PB-650
PB-750
Main jet
#58.5
#50
(PB-750)