TRICKY QUESTION..,20631 used EXCEPT when using flywheel 206-750 and magneto 320-746 Bendix K2A-5 So you can use KE7 Starter, Ratchet Nut on KF7, KG7 or KG4, except for above flywheel magneto combination. Per the parts manual.
KE7 uses impeller 24472 KF7,KG7,,KG4 use 47-21164
Not sure which impeller chart you want, There have been several articles in Antique Outboarder regarding adapting impellers with some cort of chart included,
Good Luck
