Weak Output Or Change Of Speed; Other Engine Problems - Husqvarna K770 Workshop Manual

7.4 Weak output or change of speed

Symptom/Category Cause
Compression is good Air has gone through the fuel pipe joint.
and there is no flame
Air has gone into the fuel pipe because of a
out
crack or pin hole
Air has gone through the pulse pipe
Air has gone through the insulator and carbu-
retor installation part
Air has gone through the oil seal
There is water in the fuel
The piston is burned
Carbon blockage in the muffler
Overheating The engine is running lean
Blockage because of dirt in the air channel for
decreasing temperature
Blockage because of dirt on the cylinder fin
Low quality fuel is being used
The level of carbon has increased in the com-
bustion chamber
The spark plug tip is red hot
Other The air filter is too dirty
Too high load

7.5 Other engine problems

Symptom/Category Cause
When the engine rev- The clutch spring is broken
olution decreases, the
The clutch is open because of rusty clutch
blade does not stop
bolts
When the engine rev- The drum bearing does not move
olution increases, the
blade does not rotate
Strong vibration The blade not balanced
The vibration dampening element is broken
701 - 002 -
There are no sparks at the spark plug
There are no sparks at the spark plug
Solution
Make sure it is tight
Replace
Make sure it is tight
Replace or tighten the gasket
Replace
Empty and clean the tank, then fill with good
quality fuel
Remove the burn with a file, or replace
Clean
Repair or replace the carburetor
Clean
Clean
Replace with good quality fuel
Clean
Champion RCJ 6Y/NGK BPMR 7A: Adjust to
0.5 mm
Replace the air filter
Lower the load
Solution
Replace the clutch spring of the engine
Remove corrosion from clutch bolts, apply
grease and assemble
Replace
Install a new blade. Make sure that the right
bushing is used
Replace
Troubleshooting - 77