Yamaha F100B F100C Outboards Factory Service Manual, Page 87Get this manual
Carburetor 4Check the pilot screw and needle valve for bends or wearReplace if necessaryNOTE: The float should be resting on the needle valve 5, but not compressing it Take measurements at the end of the float opposite its pivoted sideFloat height a: 12.515.5 mm (0.490.61 in)
Checking the Prime Start
1Measure the length of the Prime Start plunger2Connect the positive Prime Start blue (L) lead and the negative Prime Start black (B) lead to battery as shown3Measure the plunger length after applying power for minutesReplace if out of specification