Honda GB40 Outboard Motor Manual., Page 26Get this manual
4Remove the adjustable hanger in the manner described in section B5Remove the holder case in the manner described in section 36, Remove 10 mm hexnut and 10 mm flat washer, pulling out the driven pulley(Fig50)
7Remove the adjuster boot and loosen the adjust plate set bolt; also turn counter-clockwise the lock of the change adjust bolt for loosening(Fig51)