Craftsman 28813 Operation Manual - Page 28

ENGINE Maintenance, repair, or replacement of the emission control devices and systems, which are being done at the customers ex- pense, may be performed by any non-road engine repair establishment or individual. Warranty repairs must be performed by an authorized engine manufacturer's outlet. service TO ADJUST CARBURETOR NOTE: The carburetor on this engine is low emission. It is equipped with an idle fuel adjusting needle with a limiter cap, which allows some adjustment within the limits allowed by the cap. Do not attempt to remove the limiter cap. The limiter cap cannot be removed without breaking the adjusting needle. The carburetor has been preset at the factory and adjustment should not be nec- essary. However, minor adjustment may be required to compensate for differences in fuel, temperature, altitude or load. If the carburetor does need adjustment, proceed as follows: In general, turning idle mixture valve in (clockwise) decreases the supply of fuel to the engine giving a leaner fuel/air mix- ture. Turning the idle mixture valve out (counterclockwise) increases the supply of fuel to the engine giving a richer fuel/air mixture. IMPORTANT: Damage to the needle valve and the seat in carburetor may result if screw is turned in too tight. PRELIMINARY SETTING - 1. Air cleaner assembly must be assembled to the carburetor when making carburetor adjustments. 2. Be sure the throttle control cable is adjusted properly (see above). FINAL SETTING - 1. Start engine and allow to warm for five minutes. Make final adjustments with engine running and shift/motion control lever in neutral (N) position. 2. Move throttle control lever to slow position. With finger, rotate and hold throttle lever against idle speed screw. Turn idle speed screw to attain 1750 RPM. 3. While still holding throttle lever against idle speed screw, turn idle mixture valve full travel clockwise then coun- terclockwise until engine runs rough. Turn valve to a point midway between those two positions. Release throttle lever. ACCELERATION TEST - 4. Move throttle control lever from slow to fast position. If engine hesitates or dies, turn idle mixture valve out (coun- terclockwise) 1/8 turn. Repeat test and continue to adjust, if necessary, until engine accelerates smoothly. High speed stop is factory adjusted. Do not adjust - damage may result. IMPORTANT: Never tamper with the engine governor, which is factory set for proper engine speed. Overspeed- ing the engine above the factory high speed setting can be dangerous. If you think the engine-governed high speed needs adjusting, contact a Sears or other qualified service center, which has proper equipment and experience to make any necessary adjustments. /Throttle Idle Speed [- _ Screw d Lever Idle M_ _ With Limiter Immediately prepare your tractor for storage at the end of the season or if the trac_i_ will not be used for 30 days or more. WARNING: Never store the tractor with gasoline in the tank inside a building where fumes may reach an open flame or spark. Allow the engine to cool before storing in any enclosure. TRACTOR When tractor is to be stored for a period of time, clean it thoroughly, remove all dirt, grease, leaves, etc. Store in a clean, dry area. 1. Clean entire tractor (See "CLEANING" in the Maintenance section of this manual). 2. Inspect and replace belts, if necessary (See belt replacement instructions in 28 the Service and Adjustments section of this manual).