the lesson that should be learned here is when you get an answer to a difficult question, record it so that it doesn’t get lost.
Not to be mean-spirited or unkind, but you’re pointing out that you got an answer and didn’t absorb it, which is kind of the whole point of answering questions in the first place, in my tiny little mind anyway.
With that being said – your motor has a two-piece crankcase, which I would have thought pointed it toward being an earlier type Caille, but with the wet exhaust, so not REALLY early. I think that exhaust was standard after 1916. The flywheel, well the Cailles were at times equipped with the same magneto as the Evinrude rowboat motors, so that could ‘splain the rope sheave on the flywheel, but your motor has what is clearly a timer lever on it, which is for battery ignition only……
Your serial number on the transom bracket is the main piece that matters, looks like yours is in the 34000 range if I read it correctly. Ther are plenty of Cailles with higher s/n’s than that, its in the middle somewhere, and I’d bet likely in the 1917-18 range. Hint – according to my books, it seems that Caille Neptunes were only sold with fixed propellers (like yours); but if it had a variable-pitch prop, it was sold as a "Caille 5-Speed".
Here’s some shit I dug up, you can use it, or not, up to you.
Hope it helps.
Best,
PM T2
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...