Home › Forum › Ask A Member › Evinrude 7516 7.5 hp Fleetwin Flywheel nut size? › Re: Evinrude 7516 7.5 hp Fleetwin Flywheel nut size?
The tap drill size for a 1/2-20 is 0.453" for standard 70% depth of thread. The ID of the nut may actually be a little larger due to the use of rolled or formed threads in mass produced fasteners, but that will get you close. For peace of mind I doubt it’s metric. The closest size would be M12 and that is quite a bit small so it won’t go far if it will even start. The next normal size up is M16 and that’s WAY too big. I’m not sure, but the OEM flywheel nut may be a different thread class for a more snug fit. They don’t typically feel as sloppy as a hardware store fastener to me.
-Ben
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