Yamaha F100B F100C Outboards Factory Service Manual, Page 112Get this manual
Power unit
CAUTION:
Do not twist, turn inside out, or bend the timing belt beyond the maximum limit of 25 mm (1.0 in) e, otherwise it may be damaged Do not get oil or grease on the timing belt5Install the tensioner 8, spring 9, and bolts, and then tighten the bolts finger tight
S60C5240
3Check that the hole on the retaining plate is aligned with the notch on the cylinder block