Fuel System - Stihl 020 T Service Manual

Condition
Machine losing chain oil
Oil pump delivers too
little oil
2.6

Fuel System

Condition
Carburetor floods;
engine stalls
Poor acceleration
STIHL 020 T
Cause
Bore in pump housing
worn
Control screw and/or control
edge on pump piston worn
Bore in pump housing
Cause
Inlet needle not sealing.
Foreign matter in valve seat or
cone damaged
Inlet control lever sticking on
spindle
Helical spring not located on
nipple of inlet control lever
Perforated disc on diaphragm is
deformed and presses constantly
against inlet control lever Inlet
control lever too high (relative to
design position)
Idle jet "too lean"
Main jet "too lean"
Inlet control lever too low
(relative to design position)
Inlet needle sticking to valve
seat
Connecting bore to atmosphere
blocked
Remedy
Fit new pump housing
Fit new control screw and/or
pump piston
Fit new pump housing
worn
Remedy
Remove and clean or replace
inlet needle, clean fuel tank,
pickup body and fuel line if
necessary
Free off inlet control lever
Remove inlet control lever
and refit correctly
Fit new metering diaphragm
Set inlet control lever flush with
bottom of metering chamber
Back off low speed adjusting
screw slightly (see Carburetor
Adjustment)
Back off high speed adjusting
screw slightly (see Carburetor
Adjustment)
Set inlet control lever flush with
bottom of metering chamber
Remove inlet needle, clean and
refit
Clean bore
10