Echo PB-251 Operator's Manual page 23

Maintenance and care
Cooling system maintenance
IMPORTANT
To maintain proper engine operating temperature, cooling air must pass freely through the cylinder fin area. This flow of air car-
ries combustion heat away from the engine.
Overheating and engine seizure can occur when:
Air intakes are blocked, preventing cooling air from reaching the cylinder,
or
Dust and grass build up on the out side of the cylinder. This build-up insulates the engine and prevents the heat from leaving.
Removal of cooling passage blockages or cleaning of cylinder fins is considered "Normal Maintenance". Any resultant failure
attributed to lack of maintenance is not warranted.
operating choke twice to clear air from carburetor chambers.
3. Check idle speed and reset if necessary. If a tachometer is
available, idle speed screw should be set to the specifica-
tions found on Page 26"Specifications" of this manual. Turn
idle screw clockwise to increase idle speed; counter clock-
wise to decrease idle speed.
Tools required: 4mm x 130 mm (5") long hex wrench, cleaning
brush
Parts required: None, if you are careful.
Cleaning Grill
1. Brush accumulated debris from crankcase intake grill above
the fuel tank.
IMPORTANT
Do not over-tighten screws, otherwise mounting holes may be-
come stripped.
Cleaning Cylinder Fins
1. Remove engine cover (two screws), pull cover away from
engine. Clean cylinder fins to allow cooling air to pass freely.
2. Loosely reassemble engine cover with two screws.
3. Tighten all screws securely.
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