Nice find! What an excellent low cost workhorse
What size is written on the sidewall? These trikes are in use around the world so there must be a size available.
Ditto on the carb. The main jet or the needle valve probably has a bit of crust grown on it from drying up periodically. Floats too. Depending on your altitude, you may get some better behavior with minor jetting changes once it is clean and tested.
That sure looks like a standard CG230 clone on the front and top end, and an interesting driveshaft conversion where the sprocket would be. Can you find a model number on the crankcase facing left in front of/under that output shaft? Maybe something like 167FM ? This series is designed from the Honda CG125 engines. Extremely dependable pushrod valve train. If it's running well now, just keep good oil in it and keep the valves adjusted. It will probably last and last that way!