Ryobi 720r, Operator'S Manual

Page: 17 / 68

MAINTENANCE AND REPAIR INSTRUCTIONS
17
Fig. 28
CARBURETOR ADJUSTMENT
The idle speed of the engine is adjustable through the
Air filter/Muffler cover (Fig. 28).
NOTE: Careless adjustments can seriously damage your
unit. An authorized service dealer should make
carburetor adjustments.
Check Fuel Mixture
Old and/or improperly mixed fuel is usually the reason
for the unit not running properly. Drain and refill the tank
with fresh, properly mixed fuel prior to making any
adjustments. Refer to
Oil and Fuel Information Pg. 9.
Clean Air Filter
The condition of the air filter is important to the operation
of the unit. A dirty air filter will restrict air flow and
change the air/fuel mixture. This is often mistaken for an
out of adjustment carburetor. Check the condition of the
air filter before adjusting the idle speed screw. Refer to
Air Filter Maintenance Pg. 16.
Adjust Idle Speed Screw
WARNING: The cutting attachment may be
spinning during idle speed adjustments.
Wear protective clothing and observe all
safety instructions to prevent serious
personal injury.
NOTE: The cutting attachment should not rotate when
the engine idles.
3. If the cutting attachment rotates when the engine
idles, turn the idle speed screw counterclockwise
1/8 of a turn at a time (as needed), to reduce idle
speed.
Checking the fuel mixture, cleaning the air filter, and
adjusting the idle speed screw should solve most engine
problems.
If not and:
• The engine will not idle,
• The engine hesitates or stalls on acceleration,
• There is a loss of engine power,
have the carburetor adjusted by an authorized service
dealer.
WARNING:
When the unit is turned off make
sure the cutting attachment has stopped
before the unit is set down to prevent serious
personal injury.
Idle Speed Screw
6. Replace the air filter inside the air filter/muffler cover
(Fig. 24).
NOTE: Operating the unit without the air filter and air
filter/muffler cover assembly, will VOID the
warranty.
Reinstalling the Air filter/Muffler Cover
1. Place the air filter/muffler cover over the back of the
carburetor and muffler.
NOTE: The choke lever must be in the PARTIAL choke
position ( B ) (Fig. 23) to install the air filter/muffler
cover.
2. Insert the four (4) screws into the holes in the air
filter/muffler cover (Fig. 23) and tighten.
Do not over tighten.
5. Squeeze the filter to spread and remove excess oil
(Fig. 27).
Fig. 27
If after checking the fuel mixture and cleaning the
air filter the engine still will not idle, adjust the idle speed
screw as follows.
1. Start the engine and let it run about 2-3 minutes at a
high speed (full throttle) to warm up. See
Starting/Stopping Instructions , Pg. 10.
2. Release the throttle trigger and let the engine idle. If
the engine stops, insert a small phillips or flat blade
screwdriver into the hole in the air filter/muffler cover
(Fig. 28). Turn the idle speed screw in,
clockwise ,
1/8 of a turn at a time (as needed) until the engine
idles smoothly.