I had a similar problem on a Mac Timberbear that Bruce helped me out on - put a new kit in the carb and it would run fine for a few minutes then flood out. Only thing to make it run again was to take the carb off, clean, and it would run again for a few minutes. What worked for me was to clean the needle seat with a toothpick (or sharpen a match stick)and a very small amount of fine valve lapping compound as there was a small amount of trash or buildup on the needle seat causing the carb to flood the engine. Make sure to clean the needle seat out with some carb cleaner after using the lapping compound.
