7. Muffler
WARNING
Regularly inspect the muffler for loose fastening screws,
damage and rust. If you find that exhaust gas leaking re-
move the muffler. Remove carbon from exhaust port using a
piece of wood or plastic. Make sure no carbon falls inside of
the engine.
1. Removing the underside guard
Confirm that the chain break is released and remove the
chain cover. Next, remove the screws of the recoil case and
the screws of the chain catcher. Draw the underside guard
out in the horizontal direction and remove it from the pin of
the engine case in the downward direction.
Chain cover
Chain catcher
2. Removing the muffler
Remove the screws and nuts attaching the muffler and re-
move the muffler.
10. Maintenance of Saw Chain and Guide Bar
■ Saw Chain
WARNING
It is very important for smooth and safe operation to
always keep the cutters sharp.
The cutters need to be sharpened when:
• Sawdust becomes powder-like.
• You need extra force to saw in.
• The cut path does not go straight.
• Vibration increases.
• Fuel consumption increases.
Cutter setting standards:
WARNING
Be sure to wear safety gloves.
Before filing:
• Make sure the saw chain is held securely.
• Make sure the engine is stopped.
• Use a round file of proper size for the chain.
Chain type:
91VG
File size:
5/32 in (4.0 mm)
3. Removing the spark arrester
Lift up the claw of the guide muffler to take it off in the up-
ward direction, and remove the arrester.
WARNING
Right after stopping the engine, do not touch the muffler
with one's bare hands. It will cause to burn your hands.
If carbon clogs between the muffler, it will cause poor-output
and the trouble in starting. After each 100 hours, check and
clean inside the muffler.
Underside guard
8. Spark arrester
The spark arrester is installed to prevent that burnt carbon is
discharged from the muffler tail. Regularly clean it with a wire
brush or a similar tool to remove the carbon.
Never use a muffler if the spark arrester is missing or defec-
tive.
Muffler
9. Exhaust port
Remove the muffler, insert a screwdriver into the vent, and wipe
away any carbon buildup after every 100 hours of use. Wipe
away any carbon buildup on the muffler exhaust vent and the
clean cylinder exhaust port at the same time.
Place the file on the cutter and push straight forward.
Keep the file position as illustrated.
After each cutter has been filed, check the depth gauge
and file it to the proper level as illustrated.
Appropriate gauge checker
Depth gauge standard
NOTE
Make the shoulder round
.025≤ ≤ ≤ ≤ ≤ (0.64 mm)
GZ3500T
Guide muffler
Spark arrester
U
S
US-15