Poulan 1994-01 User Manual - Page 19

D. CARBURETOR ADJUSTMENTS NOTE: Thisis a complicated task. Readallwarnings andinstructions thoroughlybefore startingadjustments. If you do not think that you completelyunderstand all warnings and instructions, let your Authorized Service Dealer perform these adjustments. A DANGER Make carburetor adjustments with the lower end supported to prevent blade or trimmer line from contacting any object. Hold unit with your hand;do not useoptionalshoulderstrapfor support. A WARNING Keep others awaywhen making carburetor adjustments. A WARNING Seriousinjuryto the operator andotherscanoccur if the carburetor is not properly adjusted. • Poor engine performance can be a result of other causes such as dirty air filter, carbon build-up on muffler outlets, etc. See "Trouble Shooting Chart" before proceeding with carburetor adjustments. • The carburetor has been carefullyadjusted however;thoeperator must be sure that adjustments are made when anyof the conditions occurasmentioned on the nest page in "Trouble Shooting Suggestions". • Very small adjustments can affect engine performance. It isimportant to turn thescrewa 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. • This is a complicated task and it is important to follow instructions in sequence as indicated. 1. TROUBLE SHOOTING SUGGESTIONS - Engine will not continue to run at idle posi- tion. See "Idle Speed Adjustment" and "Low Speed Mixture Adjustment." - Blade or trimmer head continues to spin when the engine idles. See "Idle Speed Adjustment" and "Deceleration Check." - Engine dies or hesitates when it should accelerate. See "Acceleration Check." - Loss of cutting power which cannot be corrected by cleaning the air filter. See "High Speed Mixture Adjustment." - Engine does not return to idle from full throttle within 2 seconds. See "Deceleration Check" - Engine will not run. See "Trouble Shooting Chart." Then, if the carburetor requires adjustment, begin with "Basic Carburetor Settings." A WARNING The blade or trimmer line will be spinning during most of this procedure. Wear protective equipment and observe all safety instructions. 2. BASIC CARBURETOR SETTINGS NOTE: In most cases,your engine can bemade to run properly with minor carburetor adjustments. Refer to."Trouble Shooting Suggestions" in the left column for the condition you are experiencing and follow the instructions. The basic carburetor settings are provided below. a. Turnthelowspeed mixture screwand thehigh speed mixture screw (Figure 25 ) clockwise until they stop. Do not turn the screws until they are tight as damage to the needle seats can occur b. Turn the low speed mixture and high speed mixture screws between three-quarters and one full turn counterclockwise. 3. ADJUSTING PROCEDURE a PREPARATION 1. Usea fresh fuel mix. See "FueliogYour En- gine." 2. Make sure the line extends to the length al- lowed by the line limiter to provide correct load on engine. 3. Start the engine. Cut grass for 3 minutes to warm engine. The engine must be at operat- i e re before carburetor adjust. ments can be performed correctly. b. IDLE SPEED ADJUSTMENT 1. Allow engine to idle. 2. Adjust idle speed screw (Figure 25 ) until engine continues to run without stalling and without blade or trimmer head moving. - Turn screw clockwise to increase engine speed if the engine stalls or dies. - Turn screw counterclockwise to slow engine down and/or to keep bladc or trim- mer head from turning. 3. Follow instructions in "Acceleration Check" and "Deceleration Check." 4. No further adjustments are necessary if the blade or trimmer head does not turn at idle speed and if performance is satisfactory. A WARNING Recheck idle speed after each adjustment. The blade or trimmer head must not turn at idle speed to avoid serious injury to the operator and others. c. ACCELERATION CHECK L Allow engine to idle. 2. Squeeze trigger fully a. If performance is satisfactory, proceed to "d. Deceleration Check." b. If the engine does not accelerate smoothly, turn the low speed mixture screw (Figure 25) counterclockwise a small amount (no more than the width of the slot in the adjusting screw). 3. Repeat step "2.)" until smooth acceleration is obtained. NOTE: It maybe necessary to repeat "Idle Speed Adjustment" through "Acceleration Check," to obtain correct adjustments. 4. Follow instructions in "Deceleration Check." - 19 -