Carburetor Adjustment - Ryobi 280r Operator's Manual

MAINTENANCE AND REPAIR INSTRUCTIONS
8. Place heat shield/muffler on a flat, stable surface with
the heat shield facing down. Reinstall the spark
arrestor by pressing it into the recessed hole in the
muffler. Make sure it fits tightly against the muffler
and is not raised up, bent, or wrinkled once in place.
9. Pick up the unit. If necessary, align muffler bolt holes
with the bolt holes in heat shield. Insert muffler
mounting bolts into holes of heat shield and through
the muffler.
10. Place heat shield/muffler on a flat, stable surface with
the heat shield facing down. Place exhaust gasket
over bolts sticking through the muffler and on top of
the spark arrestor (Fig. 28).
11. Hold heat shield/muffler with finger over the exhaust
gasket to keep it in place. Turn over and align bolts
with bolt holes in the engine. Push bolts into the
engine holes and release the gasket once the bolts
are started. Do not tighten bolts completely.
12. Reinstall four (4) screws to attach top heat shield to
bottom heat shield.
13. Tighten muffler mounting bolts.
14. Reassemble the housing unit. Realign the two
housing units and screw holes. Make sure all wires
and other parts are completely within the housing
units and are not crimped, pinched, or sticking out.
Reinstall the 10 screws.

CARBURETOR ADJUSTMENT

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.
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 adjuster.
Refer to Air Filter Maintenance.
Adjusting the Carburetor
If after checking the fuel mixture and cleaning the air
filter the engine still will not idle, adjust the idle speed as
follows.
1. Make the initial settings with the engine stopped.
These initial settings should allow you to start and
warm up the unit before making the final adjustments.
WARNING: Wear protective clothing and
observe all safety instructions to prevent
serious personal injury.
Do not set the unit on any surface except a
clean, hard area while starting or performing
any adjustments. Debris such as gravel, sand,
dust and grass. could be picked up by the air
intake and thrown out by the discharge
opening, damaging unit, property, or causing
serious injury to bystanders or operator.
Initial Idle Speed Setting
2. Remove the air filter cover and insert a screwdriver
through the opening in the air filter base (Fig. 30).
3. Back the idle speed screw (Fig. 31) out
(counterclockwise) until it does not contact the
carburetor throttle lever. Then turn the screw in
(clockwise) until it just begins to move the throttle
lever; then continue turning for 2 more full turns.
Throttle
Lever
Idle Speed
Mixture
Needle
Idle Speed Screw
Fig. 30
Idle Speed
Screw
High Speed
Mixture
Needle
Fig. 31
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