Happy gonna-be boater here! The Golden Jubilee 5.5 runs!!
It probably runs better than I do at this age.

)
It had spark on the top cylinder but not bottom. Pulled flywheel. The coils, points, condensers, look recent and good. Gap is good, ran some emery through the points, cleaned with contact cleaner, and presto: spark from both plugs!
Filled a garbage can under the lower, hung a gravity gas tank up, and she fired up after a couple pulls! Had Quicksilver Marine TSO at 16-1 just to be sure everything had a good shot of oil after sitting for years so it smoked quite a bit.
Water spewing out of the upper discharge hole. Ran fine at the start position, revved up fine, N, F & R all work, but didn't want to idle without dying. Couldn't run long enough to warm up because reverse knocked a hole in the water can. ;-) Never saw that happen on youtube, lol.
How lean can I mix the Quicksilver for this motor?
Grabbed the QS just because it was what Napa had on the shelf.
Is there another TSO that would be significantly better?
Now I just have to clean the original pressure tank and hope it works like the motor without a complete rebuild.
Any trick or hope for low speed and idle without pulling the carb?
Any concern about the thermostat?
Remove and clean? Check in a pan of boiling water like an auto 'stat?
Thanks, Dave