10
FC 75, FC 85, FH 75, FS 75, FS 80, FS 85, HL 75, KM 85, KW 85
4.3
Fuel System
Condition
Cause
Remedy
Engine stalls at idle speed
dle jet bores or ports blocked
Clean jet bores and ports and blow
clear with compressed air
Idle jet too rich or too lean
Reset low speed screw (
L
)
correctly
Setting of idle speed screw
incorrect – throttle shutter
completely closed
Reset idle speed screw (
LA
)
correctly
Engine speed drops quickly under
load – low power
Air filter plugged
Clean the air filter or replace if
necessary
Tank vent faulty
Clean the tank vent of replace if
necessary
Leak in fuel line between tank and
fuel pump
Seal or renew connections and fuel
line
Pump diaphragm damaged or
fatigued
Fit new pump diaphragm
Main jet bores or ports blocked
Clean the bores and ports
Fuel pickup body dirty
Install new pickup body
Fuel strainer dirty
Fit new fuel strainer
Setting of high speed screw (
H
) too
rich
Reset high speed screw (
H
)
correctly
Throttle shutter not opened fully
Check linkage
Engine will not idle –
idle speed too high
Throttle shutter opened too wide by
idle speed screw
Reset idle speed screw
LA
correctly