Dolmar PS-220 TH Manuel D'instructions page 18

Denomination of components
1. Rear handle
2. Safety locking button (throttle lock)
3. Throttle lever
4. Hand guard (release for chain brake)
5. Chain
6. Guide bar
7. Guide bar case
8. Retaining nuts
9. Chain catch (safety device)
10. Sprocket cover
11. Muffler
12. Spark plug
13. Front grip (tubular handle)
14. Starter grip
15. I/STOP-switch (short-circuit switch)
16. Carabiner or rope attachment point
17. Oil tank cap
18. Fan housing with starting assembly
19. Fuel tank cap
20. Air filter cover
21. Choke lever
22. Primar pump
PUTTING INTO OPERATION (Fig. 25)
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!
Mounting the guide bar and saw chain (Fig. 26)
Use the universal wrench delivered with the chain saw for the following work.
Put the chain saw on a stable surface and carry out the following steps for mounting
the guide bar and chain:
Disengage the chain brake by pulling the hand guard (1) in the direction of the arrow.
Unscrew retaining nut (2).
Carefully spread the sprocket cover (3), pull it from its fixture (4) and remove it.
Turn the chain adjusting screw (5) to the left (counterclockwise) until the pin (6) is at
the right stop. (Fig. 27 & 28)
Position the guide bar (7). (Fig. 29)
Lift the chain (9) over the sprocket (10). Using your right hand, guide the chain into
the top guide groove (11) on the guide bar. (Fig. 30)
Note that the cutting edges along the top of the chain must point in the direc-
tion of the arrow!
Pull the chain (9) around the nose (12) of the guide bar in the direction of the arrow.
Pull the guide bar by hand fully toward its nose. Make sure that the chain blade fits
the grooves of the guide bar. (Fig. 31)
First, push the sprocket cover (3) into its fixture (4). Make sure that the pin (8) of the
chain tightener is in the hole on the guide bar. Then push it over the retaining bolt
while lifting the saw chain (9) over the chain catch (13).
Manually tighten the retaining nut (2). (Fig. 32)
Tightening the saw chain
Turn the chain adjusting screw (5) to the right (clockwise) until the chain engages the
guide groove of the bottom side of the bar (see circle).
Slightly lift the end of the guide bar and turn the chain adjusting screw (5) to the right
(clockwise) until the chain rests against the bottom side of the guide bar.
While still holding up the tip of the guide bar, tighten the retaining nuts (2) with the uni-
versal wrench. (Fig. 33)
Checking the chain tension (Fig. 34)
The tension of the chain is correct if the chain rests against the bottom side of the
guide bar and can still be easily turned by hand.
While doing so the chain brake must be released.
Check the chain tension frequently - new chains tend to get longer during use!
When checking the chain tension the engine must be switched off.
NOTE:
It is recommended to use 2 – 3 chains alternatively.
In order to guarantee uniform wear of the guide bar the bar should be turned over
whenever replacing the chain.
Chain brake (Fig. 35)
The PS-220 TH/PS-221 TH comes with an inertia chain brake as standard equip-
ment. If kickback occurs due to contact of the guide-bar tip with wood (see "SAFETY
PRECAUTIONS"), the chain brake will stop the chain through inertia if the kickback is
sufficiently strong.
The chain will stop within a fraction of a second.
The chain brake is installed to block the saw chain before starting it and to stop
it immediately in case of an emergency.
3
4
2
15
1
9
12
10
11
16
13
19
17
IMPORTANT: NEVER run the saw with the chain brake activated! Doing so can
very quickly cause extensive engine damage!
ALWAYS release the chain brake before starting the work!
NOTE:
The chain brake is a very important safety device and like any other component
subject to normal wear and tear. Regular inspection and maintenance are
important for your own safety and must be done by a DOLMAR service centre.
Engaging the chain brake
If the kickback is strong enough the sudden acceleration of the guide bar combined
with the inertia of the hand guard (1) will automatically actuate the chain brake.
To engage the chain brake manually, simply push the hand guard (1) forward
(towards the tip of the saw) with your left hand (arrow 1).
Releasing the chain brake
Pull the hand guard (1) towards you (arrow 2) until you feel it catch. The brake is now
released.
Fuel (Fig. 37)
CAUTION:
This saw is powered by mineral-oil products (gasoline (petrol) and oil).
Be especially careful when handling gasoline (petrol).
Avoid all flame or fire. Do not smoke (explosion hazard).
Fuel mixture
The engine of the chain saw is a high-efficiency two-stroke engine. It runs on a mix-
ture of gasoline and two-stroke engine oil.
The engine is designed for unleaded regular gasoline with a min. octane value of 91
ROZ. In case no such fuel is available, you can use fuel with a higher octane value.
This will not affect the engine.
In order to obtain an optimum engine output and to protect your health and the
environment use unleaded fuel only.
For lubricating the engine use a two-stroke engine oil (quality grade: JASO FC, ISO
EGO), which is added to the fuel.
Caution: Do not use ready-mixed fuel from petrol stations.
The correct mixture ratio:
25:1 i.e. mix 25 parts gasoline with 1 part oil.
NOTE:
For preparing the fuel-oil mixture first mix the entire oil quantity with half of the fuel
required, then add the remaining fuel. Shake the mixture thoroughly before pouring it
into the tank.
It is not wise to add more engine oil than specified to ensure safe operation.
This will only result in a higher production of combustion residues which will
pollute the environment and clog the exhaust channel in the cylinder as well as
the muffler. In addition, fuel consumption will rise and performance will
decrease.
The Storage of Fuel
Fuels have a limited storage life. Fuel and fuel mixtures age. Therefore fuel and fuel
mixtures, which have been stored for too long, can cause starting problems. Pur-
chase only that amount of fuel, which will be consumed over the next few months.
Store fuel safely in a dry place in approved containers only.
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5
7
6
8
15
14
22
20
18
21
(Fig. 36)
(braking)