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9
Series 4137 Components - HT
4.3
Fuel System
Condition
Cause
Remedy
Engine stalls at idle speed
Idle jet bores or ports blocked
Clean jet bores and ports and blow
clear with compressed air
Idle jet too rich
Screw home the low speed screw
slightly (see Adjusting the
Carburetor)
Setting of idle speed screw
incorrect – throttle shutter
completely closed
Set idle speed screw
correctly
Engine speed drops quickly under
load – low power
Air filter dirty
Clean or replace the air filter
Tank vent faulty
Clean tank vent or replace if
necessary
Leak in fuel line between tank and
fuel pump
Seal connections or install a new
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 a new pickup body
Fuel strainer dirty
Replace the fuel strainer
Setting of high speed screw (
H
) too
rich
Set high speed screw (
H
) correctly
Throttle shutter does not
open fully
Check throttle control
Engine will not idle,
idle speed too high
Throttle shutter opened too
wide by idle speed screw (
LA
)
Set idle speed screw (
LA
) correctly
Содержание 4137 Series
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