I would go with 24:1 for the first gallon or two. After that 50:1 should
work (assuming that the engine has needle bearings for the rods rather
than bronze bushings).
BTW, how did you clean the carbs? As I recall, that engine only had one
carb. And did you mean that you freed up the seized pistons rather than
the head?
Good luck and good boating,
Jim

Kurt wrote:
I've seen many posts about this but I'd like to double check. I've
got an old 1967 3HP Evinrude model 3716 that I'm bringing back from
the dead. So far I've freed the seized heads, rebuild the stator,
have spark, and cleaned the carbs.

It's time for fuel test, and I was wondering about the oil: gas
mixture. I've got a manual on order, but I won't get it until Monday
and would love to get it working this weekend. Should I go with the
modern 50:1 or the more classic 24:1 or 16:1? As I said I'm waiting
on the manual so I'm not sure what the original spec was. Any advice
would be greatly appreciated.

Thank you,

Kurt