Fuel System - Stihl 064 Service Manual

STIHL 064, 066
2.6

Fuel System

Condition
Carburetor floods;
engine stalls
Poor acceleration
Engine will not idle,
idle speed too high
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 is too high
(relative to design position)
Idle jet "too lean"
Main jet "too lean"
Inlet control lever is too low
(relative to design position)
Inlet needle sticking
to valve seat
Connecting bore to
atmosphere blocked
Diaphragm gasket leaking
Metering diaphragm
damaged or shrunk
Throttle valve opened too far
by idle speed adjusting screw
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
top of metering chamber face
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
top of metering chamber face
Remove inlet needle, clean
and refit
Clean bore
Fit new diaphragm gasket
Fit new metering diaphragm
Reset idle speed adjusting
screw correctly
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