Dolmar PS-220 TH Manuel D'instructions page 20

MAINTENANCE (Fig. 47)
STOP
Sharpening the saw chain
CAUTION: Before doing any work on the guide bar or chain, always switch off
the engine and pull the plug cap off the spark plug (see "Replacing the spark
plug"). Always wear protective gloves!
The chain needs sharpening when:
The sawdust produced when sawing damp wood looks like wood flour.
The chain penetrates the wood only under great pressure. The cutting edge is visibly
damaged.
The saw is pulled to the left or right when sawing. This is caused by uneven sharpen-
ing of the chain.
Important: Sharpen frequently, but without removing too much metal!
Generally, 2 or 3 strokes of the file will be enough.
Have the chain resharpened at a service centre when you have already sharpened it
yourself several times.
Proper sharpening: (Fig. 48)
CAUTION: Use only chains and guide bars designed for this saw.
All cutters must be of the same length (dimension a). Cutters with different lengths
result in rough running of the chain and can cause cracks in the chain.
Minimum cutter length is 3 mm. Do not resharpen the chain when the minimum cutter
length has been reached; at this point, the chain must be replaced.
The depth of the cut is determined by the difference in height between the depth lim-
iter (round nose) and the cutting edge.
The best results are obtained with a depth-limiter depth of 0.65 mm (.025").
CAUTION: Excessive depth increases the risk of kickback!
All cutters must be sharpened to the same angle, 30°. Different angles result in a
roughly, irregularly running chain, increase wear and tear and cause chain beakage.
The 85° front rake of the cutter results from the cut depth of the round file. If the
proper file is used in the right manner, the correct front rake will be obtained automat-
ically. (Fig. 49)
Files and how to work with them (Fig. 50)
Use a special round file for chains (dia. 4 mm) for sharpening the chain. Normal
round files are not appropriate for this work.
The file should cut only when pushed forwards (arrow). Lift the file when leading it
backwards.
First sharpen the shortest cutter. The length of this cutter is then the standard for all
other cutters of the chain.
Always guide the file horizontally (90° to the guide bar).
The file holder makes file guidance easier. It is marked for the correct 30° sharpening
angle (keep the marks parallel with the chain when filing, see illustration) and limits
the cut depth to the correct 4/5 of the file diameter. (Fig. 51)
After having sharpened the chain, the height of the depth limiter must be checked by
means of a chain gauge.
Correct even the smallest excess height with a special flat file (12).
Round off the front of the depth limiter (13). (Fig. 52)
Cleaning the sprocket interior, checking and replacing the chain catcher
(Fig. 53)
CAUTION: Before doing any work on the guide bar or chain, always switch off
the engine and pull the plug cap off the spark plug (see "Replacing the spark
plug"). Always wear protective gloves!
CAUTION: Do not start the saw until it has been completely assembled and
inspected!
Remove the sprocket cover (4) (see section on "PUTTING INTO OPERATION") and
clean the interior with a brush.
Remove the chain (3) and guide bar (2).
NOTE:
Make sure that no residue or contaminants remain in the oil guide groove (1) and the
chain tightener (6).
For replacing the guide bar, chain, and sprocket, see "PUTTING INTO OPERATION".
Chain catcher
Visually inspect the chain catcher (5) for damage and replace if necessary.
Cleaning the guide bar, lubricating the sprocket nose (Fig. 54)
CAUTION: Protective gloves must be worn.
Regularly inspect the bearing surfaces of the guide bar for damage, and clean them
with a suitable tool.
Sprocket nose type:
If the saw is used intensively it will be necessary to lubricate the return sprocket bear-
ings regularly (once a week). To do this, first thoroughly clean the 2 mm hole at the tip
of the guide bar, and then press in a small amount of multi-purpose grease.
Multi-purpose grease and grease guns are available as accessories.
Multi-purpose grease 944 360 000
Grease guns 944 350 000
Replacing the saw chain (Fig. 55)
CAUTION: Use only chains and guide bars designed for this saw.
Check the sprocket (10) before mounting a new chain.
CAUTION: Worn out sprockets may damage the new chain and must therefore be
replaced.
Replacing the suction head (Fig. 56)
The felt filter (12) of the suction head can become clogged. It is recommended to
replace the suction head once every three months in order to ensure unimpeded fuel
flow to the carburetor.
To remove the suction head for replacement, pull it out through the tank filler neck
using a piece of wire bent at one end to form a hook.
Cleaning the air filter (Fig. 57)
Unscrew screw (14) and remove the cleaner case cover (13).
IMPORTANT: Cover the intake opening with a clean cloth in order to prevent dirt par-
ticles from falling into the carburetor. Remove the air filter (15).
CAUTION: To prevent injury to the eyes, do NOT blow out dirt particles! Do not
use fuel to clean the air filter.
Clean the air filter with a soft brush.
If the filter is very dirty, clean it in lukewarm water with dishwashing detergent.
Let the air filter dry completely.
If the filter is very dirty, clean it frequently (several times a day), because only a clean
air filter provides full engine power.
CAUTION:
Replace damaged air filters immediately.
Pieces of cloth or large dirt particles can destroy the engine!
Replacing the spark plug (Fig. 58)
CAUTION:
Do not touch the spark plug or plug cap if the engine is running (high voltage).
Switch off the engine before starting any maintenance work. A hot engine can
cause burns. Wear protective gloves!
The spark plug must be replaced in case of damage to the insulator, electrode ero-
sion (burn) or if the electrodes are very dirty or oily.
Remove the cleaner case cover (see "Cleaning the air filter").
Pull the plug cap (1) off the spark plug. Use only the combination wrench supplied
with the saw to remove the spark plug.
CAUTION: Use only the following spark plugs: NGK CMR6A.
Electrode gap (Fig. 59)
The electrode gap must be 0.6 – 0.7 mm.
Cleaning the inlet port of the cooling air (Fig. 60)
Unscrew four screws (2). Remove recoil starter (3).
Clean the inlet port (4) and the cylinder fins.
Cleaning the muffler (Fig. 61)
CAUTION: If the engine is hot there is a risk of burning. Wear protective gloves.
Remove the sprocket cover (see "PUTTING INTO OPERATION").
Remove deposits of carbon from the exhaust outlets (11) of the muffler.
Cleaning the cylinder space (Fig. 62)
Remove the sprocket cover (see "PUTTING INTO OPERATION").
If necessary remove muffler by loosening and removing the two screws (14).
Stuff a rag into the cylinder port (15).
Use a suitable tool (wooden scraper) to clean out the cylinder space (16), especially
the cooling fins.
Remove the rag from the cylinder port and refit the muffler according to the diagram.
Replace the gasket (13) if necessary. Carefully remove any pieces of the old gasket
from the muffler.
Ensure correct mounting position.
The cowling should follow the contour of the cylinder to ensure correct heat transfer.
Tighten screws (14) to 10 Nm while the engine is cold.
20
STOP
STOP
STOP