Had the same issue last year. Chased down several areas that people advised on this forum to no avail. Ended up that the leak was coming from my fresh water fill port. I had to put a bead of caulk to fill the gap between the fiberglass and metal. If you can remove the three screws on your...
Had a very similar issue on my Westerbeke genset, after many attempts to start, found wire disconnected under the left side of the carb. Check that before going crazy troubleshooting.