Maintenance (continued)
Only start and use the unit when it is completely constructed. If you use the unit without all its covers fitted, you risk serious personal injury.
Carburetor
The unit’s engine is broken in after it has run through
Operation
The carburetor governs engine speed, through the throttle. Air and fuel are mixed in the carburetor, and this mixture is adjustable. This adjustment must be accurate in order to take advantage of the engine’s optimal output.
The carburetor should be set to adapt to local conditions, like altitude, climate, gas, and the type of
Basic Setting
The carburetor is configured at a basic setting at the factory, before it ships to the customer. This basic setting is richer than the optimal setting. You should keep the basic setting during the unit’s first working hours. Afterwards, the carburetor needs to be finely tuned by a skilled technician.
Fine Adjustment
After the engine has been broken in, it should be finely adjusted by a qualified technician. First adjust the L- jet, then the idling T screw, and then the
Conditions
Before making any adjustments, be sure the air filter is clean and the air filter cover is properly fitted. Any carburetor adjustment performed with a dirty air filter will result in a leaner mixture when compared with the engine performance once the air filter is cleaned. This can lead to serious engine damage.
Muffler
NOTE: Some mufflers are fitted with a catalytic converter. Refer to the Specifications to determine whether your unit is fitted with a catalytic converter.
The muffler is designed to dampen the noise level of the engine, and to direct exhaust fumes away from the user. Exhaust fumes are hot and contain sparks, which can result in fire if the fumes are direct- ed towards dry material. To prevent this, some mufflers are equipped with a spark arrestor screen.
If your unit has a spark arrestor screen, you must clean it regularly. Clean the screen with a wire brush.
On mufflers without a cat- alytic converter, clean the screen weekly, or replace it. On mufflers configured with a catalytic converter, you should check and clean the spark arrestor screen monthly.
if the screen is damaged,
you must replace it. If the screen is blocked frequently, an impaired catalytic converter may be to blame. if this is the case, contact your local dealer to inspect the muffler. A blocked spark arrestor screen will cause the engine to overheat, possibly damaging the cylinder and piston.
Never operate a unit that has a defective muffler.
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