Need parts for 1987 NS9.9B2 or 12, 15, 18 hp

I have a 1987 model Nissan NS9.9B2 motor that was running a couple of months ago. I had bought it about a year ago from a friend. I had idled it every month or so sitting in a barrel in the yard, but never had it on the water. When I did get it out on the water, it was running crappy, So I pulled the carburetor to clean it. When I did, I noticed the head of the main fuel nozzle inside the carburetor was missing. I was able to get the main nozzle out, but my search for parts has led me nowhere. I'd like to get a carb kit for it, or at least the main nozzle/jet. I'd also consider a carburetor off of a 12, 15, or 18 hp motor, as it's my understanding the hp difference is only through carburetion during those models. I'd be ok with new or used. Maybe even a parts motor from somewhere? This is a clean, low hour motor I've got, and I had it on the water for about an hour running one day. Also needs a new prop cuz the hub is slipping at higher RPMS. I didn't find the head to the jet inside the bowl, which made me wonder if it may have been sucked into the intake, but I highly doubt it because it's too large to pass through the nozzle and get inside the manifold. I feel like someone tried to clean it before and over tightened it, breaking the head off the nozzle. So they reassembled it and got rid of her. Anyhow, any help would be greatly appreciated!

Carb parts are generally NLA for that motor. 350031510M MAIN JET #108-NO LONGER AVAILABLE.
No, it is not the same motor as an 18. It shares blocks with the 12 and 15, which are also quite obsolete.
Props are still available, depending on which pitch you need.
Water pump kits are still available.
If you can find a used carb for a 9.9/12/15B2, you may be OK... but you will not find carb kits, etc., so maintaining that carb will be difficult and time-consuming at best. Essentially, it's time to retire that motor.