Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 331Get this manual
Remove rewind spring by placing sheave over pieces of wood (2 4's) with spring facing downTap top of sheave with malletThis will cause rewind spring to drop out of sheave 5Remove sheave from vise and remove sheave shaft and bushing
Reassembly
AWARNING
When reassembling rewind starter, SAFETY GLASSES must be worn in case rewind spring uncoils out of the housingINSTALLING USED REWIND SPRING
Sheave Shaft Bushing Sheave Flat Washers (Use as Required so that Sheave Will Rotate above Vise)Hook Spring in NotchTurn Sheave Clockwise while Feeding Spring into RecessVise (with Soft Jaw Protectors)
1Lubricate rewind spring with low temperature grease2To enable sheave to rotate when installing rewind spring, place bushing and sheave shaft into sheaveAdd flat washers, below sheave to raise sheave above viseSecure sheave shaft in vise that is equipped with soft jaw protectors3Engage hook (on end of spring) into sheave4Turn sheave clockwise, while feeding spring into recess, and use thumbs to gu ide rewind spring into recessProceed cautiously; do not allow spring to get out-of-control