11Series 4144 Components FC, FS, KM
4.4 Carburetor
Condition Cause Remedy
Carburetor floods; engine stalls Inlet needle not sealing 
– foreign matter in valve seat or 
cone
Remove and clean the inlet needle, 
clean the carburetor
Inlet control lever sticking on 
spindle
Check inlet control lever, replace if 
necessary
Helical spring not located on nipple 
of inlet control lever
Remove the inlet control lever and 
refit it correctly
Perforated disc on diaphragm is 
deformed and presses constantly 
against the inlet control lever
Fit a new metering diaphragm
Metering diaphragm deformed Fit a new metering diaphragm
Poor acceleration Setting of low speed screw too lean Check basic carburetor setting, 
correct if necessary
Setting of high speed screw too 
lean
Check basic carburetor setting, 
correct if necessary
Inlet needle sticking to valve seat Remove inlet needle, clean and 
refit
Diaphragm gasket leaking Fit new diaphragm gasket
Metering diaphragm damaged or 
shrunk
Fit a new metering diaphragm
Tank vent faulty Replace tank vent
Leak in fuel hose between tank and 
fuel pump
Install new hose