Poulan 1995-03 User Manual - Page 17

F. CARBURETOR ADJUSTMENTS Carburetor adjustment is critical and if done improperly can permanently damage the engine as well as tor. Please read all instructions and consult the Troubleshooting section of this manual before beginning If the engine does not operate according to these instructions after repeating the adjusting steps, do not the carburethis process. use the unit For further assistance, contact your Authorized Service Dealer. The carburetor has been adjusted at the factory for sea level conditions. Adjustments may become necessary if the sew is used at significantly higher altitudes or if you notice any of the following conditions: • Chain moves when the engine met at idle speed. See "Idle Speed Adjustment." • Saw will not idle. See "Idle Speed Adjustment" and "Low Speed Mixture Adjustment." • Engine dies or hesitates when it should accelerate. See "Acceleration Adjustment." • Loss of cutting power which is not corrected by air filter cleaning. See "High Speed Mixture Adjustment." A WARNING The chain will be moving during most of this procedure. Wear your protective equipment and observe all safety precautions. A WARNING In "Low Speed Mixture Adjustment," recheck idle speed after each adjustment. The chain must not move at idle speed. CARBURETOR PRESETS (Figure 35) If your engine will not start due to suspected imprope carburetor adjustment, the following presets may be required. If used, it is recommended that all steps within the adjustment procedure be completed in order to assure a properly set carburetor. If presets are not needed, proceed to section "Idle Speed Adjustment." When making adjustments be careful not to force the plastic limiter caps beyond the stops or damage will OCCUr. Very small adjustments can affect engine performance. It is important to turn the screw a very small amount per adjustment and test performance before making further adjustments. Each adjustment should be no more than the width of the slot in the adjusting screw. • Turn both of the mixture screws counterclockwise until they stop. • Turn idle speed screw clockwise until it stops. Now turn counterclockwise 4 1/2 rums. • If engine fails to start after performing carburetor presets, the unit may be flooded. • Start the engine and operate for three (3) minutes to mono up. Go to "Adjusting Procedure" Idle Speed Screw - Low Speed Mixture Sc T Hill O. High Speed Mixture Screw ADJUSTING PROCEDURE Idle speed adjustment • Allow the warm engine to idle. • Adjust the idle speed screw until the engine contin- ues to run without stalling and without the chain moving. - TUT SCITIV clockwise to increase engine speed if engine stalls or dies. - Tam screw counterclockwise to slow engine down and/ to keep the chainfrom turning. • No further adjustments are necessary if the chain does not move at idle speed and if performance is satisfactory. Low speed mixture adjustment • Allow engine to idle. • Tum the low speed mixture screw slowly clockwise until the RPM starts to drop. Note the position. • Turn the low speed mixture screw counterclockwise until the RPM speeds up and starts to drop again. Note the position. • Set the low speed mixture screw at the midpoint between the two positions. High speed mixture adjustment IMPORTANT: Do not operate engine at full throttle for prolonged periods while making high speed adjustments as damage to the engine can occur. • Make a test cut. • Based on performance of the saw while cutting. adjust the high speed mixture screw in MO turn increments as follows: - Clockwise if saw smokes or loses power in the ear Do not adjust for best power by sound or speed, butjudge by how well the sawperforms in the eat - Counterclockwise if the saw has speed while out of the cut. but dies in the terse or larks power while cutting. • Repeat the test cut. • Continue with 1/16 turn adjustments until the saw performance is acceptable while cutting. • After completing adjustments, check for acceleration. Acceleration check • 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. • Check the idle speed for stability and no chain movement Adjust as necessary. • Recheck for smooth acceleration and stable idle. Repeal process as necessary far acceptable perfor- mance. 'CAUTION: IA carburetor setting that is too lean (clockwise adjustment on high speed screw for maximum speed) will cause engine damage to any 2-cycle engine from overheating and lack of lubrication. Never set the high speed screw so far clockwise that you have high engine speed lacking power to cut. An effective approach follows. - Turn high speed screw counterclockwise until engine loses power while cutting. - Turn high speed screw clockwise using I/16 turn increments only anti/ the engine has power while ad- Figure 35 - 17 -