Two observations from close study of KB-1A Owners Manual reprint…1) it is difficult to make out all but most obvious detail 2) part 117 Flywheel Nut is only and no washer or lock washer for 7/16 is listed.
I have seen rope plates with imprint of an outside tooth star lock washer, but, that may or may not be factory.. The manual does offer the option of returning your motor Mercury dealer where it will be sent to factory service department for a full rebuild to original condition. Wonder if that offer shill holds.
Louis
1940 Mercury K5 twin with Eisemann 72H magneto used an extension PLUS and internal tooth lock washer. This is a relatively original example so it appears Kiekhaefer Corporation did use them if not on all models.
Louis
