8-241234567891011EBU23940Adjusting the carburetorThe carburetor should be checked and, if neces-sary, adjusted at the intervals specified in the peri-odic maintenance and lubrication chart. Thecarburetor is an important part of the engine andrequires very sophisticated adjustment. Therefore,most carburetor adjustments should be left to aYamaha dealer, who has the necessary profes-sional knowledge and experience. The adjustmentdescribed in the following section, however, maybe performed by the owner as part of routine main-tenance.NOTICEECB00480The carburetor has been set and extensivelytested at the Yamaha factory. Changing thesesettings without sufficient technical knowl-edge may result in poor performance of ordamage to the engine.EBU24000Adjusting the engine idling speedThe engine idling speed must be checked and, ifnecessary, adjusted as follows at the intervalsspecified in the periodic maintenance and lubrica-tion chart.TIPA diagnostic tachometer is needed to make thisadjustment.1. Start the engine and warm it up.TIPThe engine is warm when it quickly responds to thethrottle.2. Attach the tachometer to the spark plug lead.3. Check the engine idling speed and, if neces-sary, adjust it to specification by turning thethrottle stop screw at the carburetor. To in-crease the engine idling speed, turn the throt-tle stop screw in direction (a), and to decreaseit, turn the screw in direction (b).
