2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 118Get this manual
Carburetor 5Measure the vacuum pressure of carburetor #4Turn the throttle valve adjusting screws to adjust the vacuum pressure of carburetors #1, #2, and #3 to the same vacuum variation as carburetor #4Inductive self-powered tachometer: YU-08036-B Digital tachometer: 90890-06760 3Open the throttle cam slowly, and check the engine speed when the acceleration pump stopper comes into contact with point
862Y4420
Adjust the engine idle speed to specification
I Engine idle speed: 900 50 rmin
8After adjusting the idle speed, rev the engine few times and let it idle for at least 15 seconds to check that the vacuum pressures stay within 50 mm Hg (67 bar, 1.97 in Hg) and to check the stability of the engine