On the one I am building now I am going to try a tilly. My other HS50 has the CHI-mikuni carb and runs fine and starts great with the enrichner. Only change was to a 125 main jet. Once I get this one finished with the tilly I will let you know how it works. I have a speedway with a 5HP briggs with a tilly on it and it is mostly stock and runs just fine with the tilly. It has a choke so 1 pull with the choke, turn it off and next pull it usually starts. I have found on non-racing applications that having the pump stack on the bottom gets rid of erratic idle issues, gas in the oil if idled, and fuel dribbles into the air filter when engine is stopped. YMMV