Repair manual

WM 80 Repair Carburetor Troubleshooting
wc_tx000522gb.fm 101
9 Carburetor Troubleshooting
9.1 Troubleshooting Walbro Carburetors
Problem Probable Cause Remedy
Engine floods. Worn inlet needle body or tip. Replace the inlet needle.
Inlet needle sticking Check spring tension and
metering lever.
Dirt or gum formations prevent-
ing the inlet needle from sealing
Remove and clean the carbure-
tor.
Metering lever set incorrectly. Adjust metering lever.
Diaphragm installed incorrectly Correct diaphragm installation.
Engine will not
accelerate.
Metering lever set too low. Adjust metering lever.
Metering lever binding. Clean metering lever.
Loose mounting bolts. Tighten mounting bolts.
Main nozzle plugged Replace the main nozzle.
Fuel hose plugged Replace the fuel hose.
Engine will not
idle.
Idle speed incorrectly adjusted Reset the idle speed.
Throttle not fully returning to idle Adjust throttle cable and inspect
the throttle shaft for sticking.
Throttle plate cocked in the bore
causing fast idle
Reposition throttle plate.
Idle discharge ports plugged Clean the carburetor or blow it
out with compressed air.
Defective manifold gaskets. Replace gaskets.
Inlet needle not seating Clean and/or replace the inlet
needle.
Engine runs rich. Defective pump diaphragm. Replace pump diaphragm.
Metering lever set too high. Adjust metering lever.
Metering lever stuck. Clean carburetor.
Worn inlet needle body or tip. Replace the inlet needle.