Poulan 1992-06 User Manual - Page 19

D. CARBURETOR ADJUSTMENTS • Poor engine performance can be a result of other causes such as dirty air filter, carbon build-up on muffler outlets, etc. See the "Trouble Shooting Chart" before proceeding with carburetor adjustments. • For best results, it is recommended that you have a qualified service dealer make all carburetor adjustments. Your dealer has the training, experience, and tools necessary to properly adjustyousawto meet our factory performancespecifications. Thisserviceisnotcovered bywarranty. If it becomes necessary for you to make carburetor adjustments yourself, follow the described procedures very carefully. • The carburetor has been adjusted at the factoryfor sea level conditions. Adjustments may become necessary if the saw is used at significantly higher altitudes or ifyou notice any of the following conditions: NOTE: Be sure to properly prepare the saw as described in "1. Preparation (below) before making any adjustments. - Chain moves when the engine runs at idle speed. See "2. Idle Speed Adjustment." - Saw will not idle. See "2. Idle Speed Adjustment" and "3. Low Speed Mixture Adjustment." -- Engine dies or hesitates when it should accelerate. See "4. Acceleration Adjustment." - Loss of cutting power which is not corrected by air filter cleaning. See "5. High Speed Mixture Adjustment." CAUTION: Permanent damage will occur to any 2-cycle engine if incorrect carburetor adjustments are made. • If the unit will not operate properly after making these adjustments, take the saw to a qualified,service dealer. A WARNING The chain will be movingduringmost of this procedure. Wear your protective gear and observe all safety precautions. 1. PREPARATION a. Stop the engine. b. Usea fresh fuel mixturewith proper gasoline/oil ratio. c. Place the saw on a solid, flat surface and make sure the chain will not contact any object. d. Locate the three (3) carburetor adjusting screw openings to the right of the air filter cover. Figure 41 . e. Start the engine and allow engine to idle three (3) minutes to warm up. The engine must be at operatingtemperatureforproperadjustments to be made. Idle Speed Screw. Low Speed Mixture Screw --sr High Speed Mixture Screw Figure 41 2. IDLE SPEED ADJUSTMENT a. Allow the engine to idle. b. Adjust the Idle Speed Screw until the engine continues to run without stalling and without the chain moving. - Turn screw clockwise to increase engine speed if engine stalls or dies. - Turn screw counterclockwise to slow engine down and/or to keep the chain front turning. c. No further adjustments are necessary if the chain does not move at idle speed and if performance is satisfactory. A WARNING In "3. Low Speed Mixture Adjustment," recheck idle speed after each adjustment. The chain must not move at idle speed. 3. LOW SPEED MIXTURE ADJUSTMENT a. Allow engine to idle. b. Turn the Low Speed Mixture Screw slowly clockwise until the RPM starts to drop. Note the position. c. Turn the Low Speed Mixture Screw slowly counterclockwise until the RPM speeds up and starts to drop again. Note the position. d. Set the Low Speed Mixture Screw at the midpoint between the two positions. 4. ACCELERATION ADJUSTMENT If the engine dies or hesitates instead of accelerating, turn the Low Speed Mixture Screw 1/16 of a turn at a time counterclockwise until you have smooth acceleration. 5. HIGH SPEED MIXTURE ADJUSTMENT CAUTION: Adjustments as small as 1/16 of a turn can affect engine performance. It is important to turn the screw only 1/16 of a turn per adjustment and test the performance of the saw before making further adjustments. a. Make a test cut. b. Adjust the High Speed Mixture Screw1/16 of a turn as follows: -- Clockwise if saw smokes or loses power. -- Counterclockwise if the saw has speed out of the cut but lacks power in the cut. c. Repeat test cut. d. Continue 1/16 of a turn adjustments until the saw runs smoothly in cut. CAUTION: A too lean high speed setting (clockwise adjustment) will cause engine damage to any 2-cycle engine from overheating and lack of lubrication. Never set the high speed mixture screw so far clockwise that you have high speed but lack power while cutting. An effective approach follows. - Turn screw counterclockwise until engine loses power while cutting. - Then, turn screw clockwise in 1116 of a turn increments only until the engine has power while cutting. NOTE: If the unit will not operate properly after making these adjustments, take the saw to a qualified service dealer. - 19 -