Honda GB40 Outboard Motor Manual., Page 30Get this manual
3Loosen the thin rnm nut, adjust plate set bolt, and adjust plate hex bolts (four); the chain adjust bolt counterclockwise for removal the joint tube(Fig66 and 67)
4Remove the 52 mm thrust washer (nylon) from the joint tube(Fig67)
CReassembly Reassembly is the reverse of disassembly
Note Prior screw-in of the joint tube into the bottom case, screw in the longer chain adjust bolt into the bottom case the extent where becomes the same in length as the shorter one, before inserting into the threaded hole the joint tube, (Fig68)