1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 22Get this manual
Throttle linkage adjustment in carburetor Loosen the joint link set screw
1Set the shift handle to forward2Set the throttle grip to "FAST"
1Joint link set screw
By pushing down the carburetor joint link, bring the throttle lever into contact with the stopper on the fu II-open side with the throttle roller still in contact with the throttle cam, then tighten the joint link set screw