Manufactured under license of
Daewoo International Corporation, Korea
www.daewoopowerproducts.com
USER'S MANUAL
DACNQ350
Concrete cutter
Notes on maintenance:
Perform any maintenance or repair work in clean and neat environment. Use proper tools and operate
with caution.
9. Do not attempt to modify your cut-off saw in any way. Use only identical spare parts for replace-
ment.
10. The cut-off saw is only intended for cutting work and cannot be used for prying or shoveling away
any objects, or used as a grinding tool with the sides of the blade.
3. SPECIFICATIONS
1. MAIN PARTS OF DACNQ350 AND THEIR FUNCTIONS
This product is composed of two main sections: a gasoline powered 2-stroke engine and a driving/cu-
tting system. When engine speed is up to 3800 RPM, the cutting blade, driven by the engine via belt
transmission system, begins to rotate at high speed, and is ready for cutting work.
Showed below are the main parts of the DACNQ350 cut-off saw and their corresponding function
descriptions (Ref. Fig 1):
1. Blade
2. Flanges
3. Hexagon Bolt
4. Blade Guard
5. Front Handle
6. Spark Plug Cover
7. Kill Switch
8. Full Throttle Lock Button
9. Throttle Trigger
10. Rear Handle
11. Filter Cover Lock Lever
12. Air Filter
13. Choke Lever
14. Starter Grip
15. Fuel Tank Cap
16. Decompression Valve
17. Water Attachment
18. Tensioning Nut
19. Muffler
20. Blade Guard Positioning Knob
21. Shaft lock
1. Blade:
Diamond or abrasive blades. Depending on the material to be cut, these blades are made of different
materials. Be sure to choose right blade for the material being cut. The maximum diameter of the
blade for the saw is 14 inch. And the operating speed of the blade should be above or equal to 4700
RPM.
2. Flanges:
Clamp and support the diamond or abrasive blade.
3. Hexagon Bolt:
Tightens blade flange.
4. Blade Guard:
Safety guard, directs sparks and dust away from operator.
5. Front Handle:
Used to securely hold the saw while under operation.
6. Spark Plug Cover:
A removable cover for access to the spark plug
7. Kill Switch:
Engine stops when this switch is pressed and held.
8. Full throttle lock button:
Locks the throttle in full open position by pressing this button while the trigger is fully depressed.
Pressing and releasing the trigger returns the throttle to idle position.
9. Throttle trigger:
Controls engine speed by manipulating the throttle. Pulling the trigger backward opens the throttle
and the engine accelerates. Releasing the trigger slows down the engine.
10. Rear Handle:
Used to securely hold the saw while under operation.
11. Filter Cover Lock lever:
Locks the air filter cover. Pull back on the lever to open the filter cover.
12. Air Filter:
Filters dirt and debris from entering carburetor.
13. Choke Lever:
Turning this lever counter clockwise closes the carburetor. Used to prime engine (cold starting). Turn
clockwise for normal operation.
14. Starter Grip:
Pull to start engine.
15. Fuel Tank Cap:
Open this cap for filling the fuel. Close the tank for starting and operation.
16. Decompression Valve:
Press down on this valve to make starting easier. When air pressure in the engine reaches a preset
value, it automatically closes.
17. Water Attachment:
Feeds water to both sides of diamond blade. Connect to water supply for wet cutting.
18. Tensioning Nut:
For V-belt tension adjustment. Turn this nut clockwise to loosen the V-belt, turn the nut counter cloc
kwise to tension the V-belt
19. Muffler:
Reduces both noise and emissions.
20. Blade Guard Positioning Knob :
Loosen the knob to adjust blade guard position.
21. Shaft lock:
Lock the blade shaft to facilitate blade changing and installation.
2. SAFETY PRECAUTIONS
As the DACNQ350 cutoff saw is a high-speed power tool, improper use of this saw might be hazar-
dous. To avoid property damage or personal injury, it is EXTREMELY IMPROTANT to read, fully
understand, and observe the following safety precautions before operating this cut-off saw.
1. Worksite Requirements:
The worksite should be free of any materials or objects that are flammable or explosive.
Surroundings should be in order, with no clutters, having sufficient visibility, and be well ventilated.
The ground operator stands on should be non-skid. Take extreme care when working in wet and
freezing weather (rain, snow, frost, ice).
Bystanders should keep away from the saw when it is operating. Children, the handicapped and
animals should never be allowed in the work area.
Loose objects may be thrown toward the operator by the cutting tool. So position the object to be cut
securely to ensure it won’t be pushed around by the blade when cutting.
2. Blade:
Before installing a blade make sure that the maximum operating speed of the blade is above or equal
to the spindle speed of your cut-off saw. Inspect the cutting blade frequently and replace immediately
if the cutting blade is cracked or warped. Cracked or warped blades may shatter or break and cause
serious personal injury. Failure to follow these directions may cause the blade to shatter or crack in
use causing serious or fatal injury.
Never use carbide-tipped, woodcutting or circular machine blades. They can cause severe personal
injury from reactive forces, blade contact or thrown objects.
Use of the wrong cutting blade for which it was not designed may cause that blade to shatter causing
serious or fatal injury.
Only use the cutting blade approved for the type of material to be cut.
Diamond blades have a much better cutting performance than standard abrasive blades. The blades
are steel centered and diamond particles are imbedded in their cutting edges.
Wet or dry cutting is possible. Cutting wet will extend the life of your diamond blades. A water attach-
ment comes as standard equipment with the DACNQ350. Before using the water attachment make
sure that the screw that secures the outlet tube is tightened.
Always install the blade so that the arrow on the blade points in direction of the rotation of the spindle.
Before carrying or transporting your cut-off machine the engine must be off. Never leave the engine
running whilst unattended, e.g. on the ground.
Proper tension of the V-belt is important. In order to avoid a false setting, the tensioning procedure
must be followed as described in your manual. Always make sure the hexagonal collar nuts for the
cast arm are tightened securely. Check V-belt tension after one hour of operation and correct if neces-
sary.
3. Operator:
The cut-off saw is a one–person tool. So start and operate this saw without assistance.
Make sure you are in good physical condition and are not under the influence of any substance such
as drugs or alcohol which may impair vision or dexterity. Take breaks as needed to prevent you from
getting fatigued.
Never let the DACNQ350 saw run unattended. NO untrained personal should ever be allowed to use a
cut-off machine. Bystanders, especially children and animals should not be allowed in the area where
a cut-off machine is in use.
Do not lend or rent your cut-off machine without the Operation Manual. Employers should establish a
training program for operators of this saw to ensure safe operation of the DACNQ350.
Avoid loose – fitting jackets, scarf, neckties, jewelry, flared or cuffed pants, unconfined long hair or
anything that could become caught on any obstacles or moving parts of the unit. Wear overalls or long
pants to protect your legs. Do not wear shorts.
Protect your hands with gloves when handing the cut-off saw. Heavy-duty, non-slip gloves improve
your grip and protect your hands.
Use DACNQ350 cut-off saw only with both hands, keeping a firm grip on the front and rear handles.
Maintain good balance and footing at all times.
Good footing is most important. Wear sturdy boots with nonskid soles. Steel-toed safety boots are
recommended.
To reduce the risk of injury to your eyes, never operate the cut-off saw unless wearing goggles or
properly fitted safety glasses with adequate top and side protection. Proper eye protection is a must!
Wear an approved safety hard hat to protect your head. Cut-off machine noise could damage your
hearing. Earplugs or ear mufflers shall be worn at all times.
Cutting masonry, concrete, metal and other materials can generate dust, mists and fumes containing
chemicals known to cause serious or fatal injury or illness, such as respiratory disease, cancer, birth
defects or other reproductive harm. Cutting masonry, concrete and other materials with silica in their
composition may give off dust containing crystalline silica. Silica is a basic component of sand,
quartz, brick clay, granite and numerous other minerals and rocks. Use of an approved respirator is
recommended.
Do not cut materials containing asbestos as asbestos dust can cause severe physical injury. Do not
cut materials containing highly volatile or flammable substances.
4. Inspection of the cutoff saw before use:
Make sure there are no loose objects on or near the saw.
Except for the carburetor adjustment screws, all other bolts, nuts, screws and the fuel tank cap should
be securely tightened. Make sure all rubber hoses for oil flow are tightly connected with no leaks.
Make sure the blade rotates smoothly; the starter rope can be pulled through and guided back without
being tangled.
Check to make sure the Throttle Trigger, the Full Throttle Lock Button, the Choke Lever, the Decom-
pression Valve and the kill Switch all function well without failure.
Check to make sure the blade guard has no visual damage. Adjust the guard as necessary so the
spark beam generated during cutting can be directed away from the operator. (Ref. Fig.2)
Check to make sure the V-belt is properly tensioned.
Make sure the saw is free of oil spillage.
Make sure the main cover and the handles are dry and clean.
Do not attempt to start the saw if damage is found or if it’s not completely and securely assembled
and properly adjusted.
5. Precautions on starting:
Keep a good balance and secure footing.
Take hold of the starter grip firmly; do not wrap the rope around your hand.
To start, place the machine firmly against the ground and make sure the blade is not in contact with
the ground or the object to be cut.
Pull sharply on the rope and guide it back slowly. Do not let go of the grip halfway through the pull to
prevent it from snapping back.
6. Precautions on operation:
Keep a good balance and secure footing while holding the saw firmly at all times.
(Ref. Fig.3)
Press the throttle trigger backward slowly to make the engine accelerate gradually. Wait until the blade
builds up the rpm’s before beginning to work.
Move the rotating blade slowly toward the object to be cut, increase the pressure gradually after the
cutting edge comes in contact with the object. Make sure the cutting depth is appropriate.
Do not change direction of the cut or twist during the cut as this may produce a high torsion load on
the blade and may cause it to break or shatter. Only move the machine along a straight line, forward or
“to and fro” in the cutting direction.
When cutting, position the saw at an appropriate distance so that your body is clear of the blade
attachment yet you don’t have to overreach.
Release the pressure on the saw when the blade completes a cut. The cut-off portion of the object
may drop, so make sure it won’t hit any part of your body or pinch the blade. .
Whenever you hear an abnormal sound coming out of the cut-off saw, stop cutting immediately for
inspection (Note the muffler and the blade are very hot at this time. so take care not to get burned).
Only resume work after the trouble is eliminated
Do not make adjustments or any other maintenance or troubleshooting with the cut-off saw while it is
running.
Take precaution when re-entering a cut and do not turn the blade at an angle or push it into the cut as
this may result in a pinching of the blade.
7. Precautions on fueling:
Fuel the machine only in a well-ventilated environment.
Before refueling, let the engine cool off naturally. Do not take any other forceful measures to cool the
engine down.
Remove the fuel tank cap carefully so as to allow any pressure build-up in the tank to release slowly.
(Ref. Fig.4)
Tighten fuel cap securely after fueling and clean off spillage if any.
8. Notes on transporting:
Always stop the engine before relocating the saw.
When carrying the machine with a hot engine, take care not to have your body get burned by the
muffler.
Prevent the saw from touching the ground or any hard objects
Operation Guide to DACNQ350 cut-off saw
1. Before starting
Preparation includes clear up and arrangement of work surroundings, wearing proper clothing and
protection and inspecting of the cut-off saw. In preparation, please follow the procedures described
in the appropriate section of this manual. For additional preparation work before starting, please
follow instructions given below:
Fueling:
a) Before starting, check if there is any fuel left in the fuel tank.
b) This engine is engineered to operate on mixture of unleaded gasoline and quality two-stroke engine
oil. Octane rating of the gasoline should at least be 93.
c) Gas to Oil mix ratio is 50:1.
d) When mixing fuel, pour engine oil into the canister first, and then add gasoline (make sure the mix
ratio is 50:1). Shake the mixture in the canister thoroughly. Clean the fuel tank cap and the area around
it as necessary to ensure no dirt falls into the tank. Finally pour the fuel mixture into the tank and
tighten fuel tank cap securely.
e) Only mix sufficient fuel for a few days work, the maximum storage time of mixed fuel is 3 months.
Choosing the right blade:
a. Blade diameter can be 300 mm (12”) or 355 mm (14”). Choose an appropriate size and type of blade
which best suits the cutting work, the blade size needs to be fitted with the blade guard. The diameter
of the arbor hole should match that of the blade shaft (1” or 20mm or other sizes depending on the
different country standards). Blade thickness should be within the range of 2.6-6 mm (.100” – .240”).
b. Blade types:
For your reference, choose composite abrasive blades for cutting of asphalt, concrete, stone, brick,
steel and plastics. Choose diamond abrasive blades for cutting of Asphalt, Concrete, Stone, Hard
rock, Brick, etc.
Note: There is a rotation direction indicator marked on each diamond blade. When mounting, make
sure it corresponds to the rotation direction of the arbor.
If you are not sure which blades are proper for your cutting jobs, contact your dealer or distributor for
information.
c. Fitting/Replacing the blade: (Ref. Fig.5)
Gently press down on the shaft lock (1), use the combination wrench to turn the blade (5) back and
forth until the shaft lock engages in the blade shaft.
Use the combination wrench to loosen and unscrew the hexagon bolt (2).
Remove the metal washer (3), the flange (4) from the blade shaft together with the blade to be repla-
ced.
Mount the new blade.
Fit the flange(4) and metal washer(3).
Screw in the hexagon bolt (2) and tighten it with the combination wrench.
Finally let go of the shaft lock so that the blade can turn freely.
Tensioning the V-belt: (Ref. Fig.6)
Loosen and unscrew the hexagon bolts (1) on the transmission box and then remove transmission box
cover (2).
Loosen the three hexagon bolts (5) on the bearing plate.
Turn the tensioning nut (6) clockwise (or turn the adjusting bolt (3) clockwise) until the V-belt is tensio-
ned.
Tighten the three hexagon bolts (5) on the bearing plate.
Fit the transmission box cover (2) and fit and tighten the hexagon bolts (1).
2.Starting (Ref. Fig.7)
Place the cut-off saw on the ground and make sure it’s in good balance, see to it that the saw blade
does not touch any objects or the ground, and there is no person within the swivel range of the saw.
Press the button of the decompression valve (1).
Set the choke lever (2) to an appropriate position:
to if the engine is cold;
to if the engine is warm(even if the engine has already run but is still cold);
to if the engine is warm (latched position for warm start).
Pull the throttle trigger (3) backward as far as the stop and hold it in position.
Press down the full throttle lock button (4).
Release the throttle trigger (3).
Hold the front handle with left hand and firmly press the cut-off saw against ground , place the right
foot on the carburetor box cover.
Holding the starter grip (5) securely, slowly pull out the starter rope for a short distance, and then pull
it through quickly and strongly.
Note: a. Starter rope is 1.15m long, do not pull the rope out more than it’s length otherwise it may
break or cause damage to the starting system.
b. Do not let go of the starter grip.
c. After pulling, guide the rope back into place slowly.
d. Pull the rope only straight up and down through the rope guide bushing to prevent it from wearing.
After the rope has been pulled through:
a. If the engine does not start, press the button of the decompression valve again and restart the
engine.
b. If the engine runs for a while but doesn’t keep running, press the decompression valve in, move the
choke lever to and then restart the engine.
c. As soon as the engine is running, briefly blip the throttle trigger (3) at once. The full throttle lock
button (4) reverts to its original position and the engine idles.
If the engine is new, or has been stored for a long period of time, pull the starter rope through several
times to ensure that sufficient fuel is delivered into the fuel line and combustion chamber of the
engine.
Fig. 7
3. Operation (Ref. Fig.7)
The blade will not run when the engine idles.
When the cut-off saw is ready for actual cutting work, gently pull the throttle trigger (3) backward to
accelerate the engine, when the speed is over 3800 rpm, the blade begins to rotate and speeds up.
When the blade speed is up and stable, you can begin to move the saw slowly toward the object to be
cut. After the cutting edge comes in contact with the object, increase pressure to the saw slowly until
the blade is at the desired depth. Finally hold the machine securely and move along a straight line to
complete the cut.
To stop or halt the cut (when a cut is completed, or the engine runs out of fuel halfway, or abnormal
sound is heard), first lift the blade out of the cut, then release the throttle trigger, wait until the engine
slows down to idle speed and the blade stops running, then finally turn off the machine.
4. Emergency stopping (Ref. Fig.8)
Under normal conditions, the machine is to be turned off when the engine idles. However, if a malfunc-
tion or emergency occurs during cutting, you can stop the engine immediately by pressing and
holding the kill switch (2) on the front end of the rear handle (1). But note that the service life of some
components of the saw may be adversely affected if the engine is stopped too often during cutting.
5. Notes on operation
Follow all applicable instructions in this manual when operating the cut-off saw.
During the break-in phase, which takes about 8 hours, the saw must not be operated at high speeds
without load (better do not pull the throttle trigger beyond 3/4 of full throttle.). Following this procedure
will lengthen the service life of your machine.
After the saw works for a certain period of time, let the engine idle on for a while to dissipate the heat.
This will prevent some engine parts (ignition system, carburetor etc.) from being damaged by over
heating.
Adjustment of DACNQ350 cut-off saw
1. Adjusting V-belt tension
Refer to the instruction described above in the section titled “Tensioning the V-belt”.
2. Adjusting carburetor
The carburetor has been preset and adjusted at the factory to reach the optimum fuel-air mixture for a
smooth, fuel efficient, reliable running engine with low emissions. The air filter and the spark plug need
to be checked and maintained regularly. However if the cut-off saw is found to be unsatisfactory in
operation (such as the idle speed either too high or too low, or abnormal exhaust emission still
persist), a slight adjustment on the carburetor might be necessary, which includes: (Ref. Fig. 9)
a. Standard setting adjustment:
Find the Low Speed Adjusting Screw “L” (see Fig.9, inside
the upper hole of the carburetor seal cover), use a screw
driver to turn the screw L clockwise all the way to its end.
Then turn the screw L backwards (counter-clockwise) 360°.
b. Adjusting idling speed:
It is usually necessary to adjust the idle speed after Standard setting adjustment (a). To adjust idle
speed, start the engine first.
If the idle speed is too low, the engine may shut off after starting. In this case, make the standard
setting
first as instructed in (a), then turn the idle speed adjusting screw LA (see Fig 9,) inside the lower hole
of carburetor seal cover clockwise until the blade starts to run. Then turn the screw LA backwards
(counter-clockwise) 1/4 circle (90°).
If the idling speed is too high, the blade will run at idling speed, which is not good for the Cut-off saw.
In this case, make standard setting first, then turn the idling speed adjusting screw LA counter-cloc-
kwise until the blade stops running. Then turn the screw LA 90°further (counter-clockwise).
3. Adjusting blade guard (Ref. Fig.10)
The blade guard (1) deflects sparks from the operator. To adjust it’s position, loosen the blade guard
positioning knob (2) first, then move the blade guard to a desired position by hand. Finally retighten
the positioning knob(2) to continue cutting.
Fig. 10
Maintenance & repair of DACNQ350 cut-off saw
1. Cleaning and maintenance of the air filter
Dust and foreign build-up accumulated on the air filter may affect engine performance, increase fuel
consumption, and cause difficulty in starting. Therefore, it’s important to perform regular maintenance.
The frequency of this depends on the conditions of the cutting jobs as well as material being cut both
wet or dry. For dry cutting, maintenance is required every 48 hours. For instructions, see below (Ref.
Fig.11)
Set the choke lever to .
Pull the filter cover lock lever (7) backward to let the filter cover (1) swing open. Then take out in
succession pre-filter(2), pre-filter(3), filter housing (4), paper air filter (5), and the secondary filter(6).
Then clean and dry all these parts. Replace if any are damaged. Finally replace all of them in succes-
sion and close the filter cover.
2. Maintenance of spark plug (Ref. Fig. 12)
Wrong fuel mixture (too much engine oil in the gasoline), low quality gasoline or oil, dirty air filter,
clogged spark arrestor screen, and other unfavorable running conditions are factors affecting the
condition of the spark plug as they cause carbon deposits accumulation, which results in trouble in
engine operation. Therefore, if the engine is down on power, difficult to start or runs poorly at idling
speed, first check the spark plug.
Remove the spark plug cover (2) on the front end of the main cover (1).
Remove the plug boot (3) and the spark plug (4) in succession.
Clean off the carbon build-up on the spark plug.
Check electrode gap A to see if it is 0.5mm/0.020”, readjust if necessary.
Replace spark plug after approx.100 operating hours, or earlier if the electrodes are badly eroded. (A
BPMR7R type spark plug is recommended for replacement.)
Refit the plug boot and make sure it is snugly connected to the spark plug.
3. Replacing starter rope (Ref. Fig. 13)
The Starter rope may need to be replaced when frayed or broken.
Unscrew the screws (2) on the flywheel/starter cover (1) and remove the cover from the engine unit.
Remove the spring clip (8), remove the rope rotor (7) with pawl (9).
Using a screwdriver, unscrew the screw plug (3) on top of the starter grip, remove the starter rope (4)
out of the grip.
Put a new rope down through the grip and the rope guide bushing (5), make a simple knot at the end
of the rope and screw in the screw plug (3)
Thread the rope through the rope rotor (7) (enter from the hole on the rotor groove) and secure it with a
simple knot. (and fitting the knot into the clearance (10)).
Wind the rope around the rope rotor (7) clockwise until there is a length of 300mm left unwound..
Slip the rope rotor onto the starter post (6) and turn it back and forth a little until the anchor loop of the
rewind spring engages.
Replace the pawl (9) in the rope rotor.
Press the spring clip (8) onto the starter post and over the peg of the pawl with a screwdriver.
Note: The spring clip must point counter-clockwise.
To tension the rewind spring, first guide the rope through the notch on the edge of the rope rotor and
form a loop, use it to turn the rope rotor 4-5 times counter-clockwise.
Then hold the rope rotor tight, pull out the twisted rope and untangle it.
Release the rope rotor, slowly let go of the starter rope so that it is wound up on the rope rotor.
Refit the flywheel/starter cover (1) and screw in the four screws (2).
4. Replacing pawl (Ref. Fig. 13)
The pawl functions as a link between the rope rotor and the crankshaft (by engaging and disengaging
the starter cup) and needs to be replaced if damaged.
Unscrew the screws (2) on the flywheel/starter cover (1) and remove the cover from the engine unit.
Remove the spring clip (8), Remove the damaged pawl (9).
Replace a new pawl.
Refit the spring clip (8) and the flywheel/starter cover (1) in succession.
Fig. 13
5. Maintenance chart
The following information refers to normal operating conditions. The specified intervals must be
reduced accordingly when working under aggravated conditions (severe dust formation, for example)
and with longer daily working hours.
Storing DACNQ350 cut-off saw
For long periods of storage:
1. Drain and clean the fuel tank, run engine until carburetor is dry.
2. Thoroughly clean the cut-off saw; tighten all nuts and bolts (except for adjusting screws).
3. Remove the blade and loosen the V-belt.
Notes on transport and storage:
1. Avoid knocks and bumps.
2. Abrasive blades must not be exposed to direct sunlight or other sources of heat during transport
and storage.
3. Store the machine in a place free of moisture and heat source, Store the cut-off saw preferably in a
place with consistent temperature. Do not store it near corrosive liquids.
4. Composite blade must be protected against frost.
4. EXPLODED PARTS VIEWS AND PARTS LISTS
1. Crankshaft Housing Assembly
2. Crankshaft & Piston Assembly
3. Cylinder & Muffler Assembly
4. Oil Tank & Carburetor
5. Handle & Main Cover Assembly
6. Air Filter Assembly
7. Transmission Box & Cutter Assembly
