I have a PPT-2400 Echo pole saw that runs for 5 minutes, stops as if it's not getting gas, and will not crank again until it cools off. Once cool, it cranks right up again. I've replaced fuel lines, fuel filter, carburetor, spark plug and ignition coil but still the same problem. I've also observed that there is fuel in the primer bulb when it stops. Don't know where to go from here. Any suggestions would be appreciated.