No disrespect, and it’s an interesting concept, but it seems way overthought. Those carbs work fine. I even found primer pump washers for mine that worked with a minor mod. The big issue is making sure the spark plug wires have hoods on them to prevent sparking as mentioned elsewhere.

But yeah. Just seems like reinventing a mousetrap that needn’t be.

If you’re going to all that trouble, maybe pick up a dirt cheap OMC-built Sea King or Gale 5hp for 45 or 50 bucks and know it’s not gonna blow up and will always run.

However if this is an issue of a vintage craft with a cool motor, maybe it make sense.

Good luck. Hope to see how it turns out. I really am interested.

Greg