I just bought a 78 446 with the original 16 hp onan. It was running a little rough when I picked it up so I drained the fuel tank, installed new fuel line, filter, plugs, carb/ fuel pump kit. It idles great with no choke, but to maintain a higher RPM I have to choke it about half way. Then I have to slowly engage the snow blower or it will stall out. With the air cleaner cover off, when I engage the blower at idle and then raise the RPMs, the carb will dump fuel into the engine, then it stalls out. Any help would be greatly appreciated. Thanks.