Husqvarna SM 50 / 2011, Workshop Manual

Page: 20 / 150

C.2 Ed. 0-09-2010
TROUBLESHOOTING
ENGINE
Trouble Cause Remedy
Engine does not start or Insufficient compression
has starting trouble 1. Piston seized Replace
2. Connecting rod small or big end seized Replace
3. Worn piston rings Replace
4. Worn cylinder Replace
5. Cylinder head loosely tightened Tighten
6. Head gasket leaking Replace
7. Spark plug loose Tighten
Weak or no spark
1. Spark plug faulty Replace
2. Fouled or wet spark plug Clean or dry
3. Spark plug electrode gap too wide Adjust
4. Ignition coil faulty Replace
5. High-tension cables open circuit or shorted Check
Fuel does not reach the carburettor
1. Tank cap breather clogged Clean
2. Fuel cock clogged Clean
3. Fuel feed pipe clogged Clean
4. Filter on carburettor fitting dirty Clean
5. Floater valve or floaters faulty Replace
6. Linkage is blocking floater valve Release
Carburettor flooding
1. High fuel level in bowl Adjust
2. Floater valve or floaters worn or stuck open Replace or release
Engine stalls 1. Fouled spark plug Clean
easily 2. Carburettor jets clogged Clean
3. Low idle Adjust
Engine is noisy Noise seems to come from piston
1. Too much piston-to-cylinder clearance Replace
2. Worn piston rings or piston grooves Replace
3. Too much carbon build-up in
combustion chamber or on piston crown Clean
Noise seems to come from crankshaft
1. Worn main bearings Replace
2. Connecting rod big end has too much side
clearance or end float Replace
3. Crankshaft gear damaged Replace
4. Crankshaft locknut loose Tighten