Originally Posted by Chris Peralta

After you heat the engine you say that you have to blow on the line to get fuel there?? When you blow on the pressure line do you notice the fuel hit the HSN and sort of jump back toward the fuel tank? It sounds to me like your carb got really hot in the pre heat process and you are vapor locking. I have had this happen quite a few times when using heat guns to pre heat rather than the comp head heater. If this is what you are seeing you can blow thru the pressure line with the carb at full throttle until the fuel stays at the HSN and no longer jumps back away from the carb.... You should now be able to start it, but with the stock needle settings it may not just idle away on it's own, you may have to adjust some for your location.

If you do use a heat gun or hair dryer try to hold a thin piece of metal between the carb and the head while you pre heat.