Small Engines (Lawn Mowers, etc.): 8.5 hp Old craftsman chipper, head gasket, diaphragms

Question
It was outside for years. Changed the fuel, oil, cleaned the carb, (twice) new fuel line, spark plug. It will only start up if I dump gas into the air box. I've got many a motor going but this one has me beat. Any help would be greatly appreciated.  

Answer
Sounds like a repower to me.  Kidding, let's see if I can help.  

If you are sure the carb and tank are clean, and you have replaced all the diaphragms in the carb you need to start looking deeper into the engine.  When the piston goes down the volume of the cylinder has to be replaced by something,  It normally would pull air through the carb into the jug.  If you have a bad head gasket it will pull air from the environment instead of through the carb.  A valve that doesn't seat will cause the same problem.  Pull the head and take a look (difficulty 3 on a 1-10 scale).  Any problem will be obvious.   If there is not a problem you were probably a tightwad and didn't replace the diaphragms.