1999 Ski-Doo Factory Shop Manual Volume One, Page 149Get this manual
Section 04 ENGINE Subsection 07 (AXIAL FAN COOLING SYSTEM)
Reinstall fan assembly on fan shaftTemporarily tighten fan nut-
CAUTION
When reinstalling fan assembly, ensure that key is properly positioned into fan shaft keyway
Fan Belt Deflection Adjustment
Check fan belt deflection using ruler and fish scale positioned midway between pulleys as per following photoA03C23A