I'm working on the same engine. They're two stroke snow blower engines. yours is 3.5 to 4hp.
You can remove the plate on the bottom of the crank and bolt up a large slice of aluminum angle "L""for the motor mount. you should be able to attach the carb of your choice through the same plate. Like the old West Bend 2-cycle engines.
They're really light weight and they should scream being two cycle.