Massey Ferguson 4608-No start

[Buckey Jones]

Tractor was bought used last summer and it ran well. Then over the winter I had to use either to get it started. It didn't matter if I plugged it in or not still wouldn't start without starting fluid. The grid heater works and I have checked everything I can think of. I changed the fuel filters last fall,about 50 hrs on them so far. I have bled the fuel system more times than I can count. No smoke out of the pipe when trying to start the tractor. Anybody have any ideas that has experience with later model Massey Fergusons?