2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 123Get this manual
Power unit 2Using hexagon wrench, turn the timing belt tensioner clockwise to push the timing belt, increase strength gradually, and then insert 5.0 mm (0.2 in) pin into the hole g3Remove the timing belt from the driven sprocket side
Checking the timing belt and sprockets
1Check the interior and exterior of the timing belt for cracks, damage, or wearReplace if necessary