Makita DBC3310 Owner's And Safety Manual

Makita DBC3310 Owner's And Safety Manual Manual pdf 17 page image

17Carburetor adjustmentImportant information:The carburetor of this tool is fitted with limiter caps which restrictthe range of adjustment and prevents over-rich mixturesettings. This ensures providing good engine power andefficient fuel consumption.Before installing the limiter caps, the manufacturer performsthe „Basic Adjustment” procedure.Maximum power is achieved throughcarburetor adjust-ment. It requires a warm engine and a clean air filter andshould preferably be performed by an expert.The carburetor comes factory-set for the atmospheric pres-sure at sea-level. At other elevations and during the run-inphase with a new engine it may be necessary to adjust thecarburetor.A tachometer (order no. 950 233 210) is a must for accuratecarburetor adjustment.Before adjusting the carburetor, install the cutting tool you aregoing to use and warm up the engine by running it 3-5 min-utes.For a precise adjustment the following steps are to beperformed:1. Check adjustment2. Start engine3. Set idling speed4. Adjust speed5. Check idling speed6. Check acceleration7. Check max. speed or output8. Repeat adjustment procedure starting with step 3, untilidling speed, max. speed and acceleration are reachedwith the adjustment made.AAdjustment instructions (step 1)- Before initial operation make sure that the adjusting screws(H and L) have not been set in all the way. Limiter caps donot protect the engine from leaning.- Turn the two adjusting screws (H and L) counter-clock-wise as far as they will go.- Start the engine and let it warm up (step 2).L HBSet idling speed (step 3)- If the cutting tool turns when the engine is idling, screw thethrottle-valve stop screw (S) until the cutting tool stopsturning. The idling speed should be now 2,300-2,500 rpm/min.Adjust speed (step 4)- Set the engine speed to 13,000-13,500 RPM by adjustingthe main jet screw (H). Screwing it in makes the fuel/airmixture leaner (less fuel, more air) and increases the enginespeed.Caution:Engine speeds above 13,500 RPM reduce engine life!SHCCheck idling speed (step 5)- Now check the idle speed. It should be 2,300-2,500 RPM(the cutting tool should not turn). If necessary, adjust theidle speed with the idle jet screw (L). Turning it in increasesthe speed, and turning it out decreases it.Check acceleration (step 6)- This is the time it takes for the engine to go from idle speedto maximum speed when you press the throttle hard.- If acceleration is too slow, turn the idle screw (L) out about1/8 turn.LSTOPSTOP