Working on my John Deere 70 diesel tractor, replaced the pony motor after breaking a couple rods. Installed a used pony and it runs great. But i cannot get the diesel to start now. It ran last November when i parked it. I bled the fuel system up to the return line back to the fuel bowl, the left #3 bleed plug won't flow anything tried to blow it with compressed air but got nothing. Should i remove the manifold that is bolted to the injectors? I was also wondering if something broke in the speed control rod for the governor when i had it loose changing the pony motor/ Looking for any help with troubleshooting.