Why is it when you park these things for the winter they are running perfect, but when you try to get them ready for harvest its a totally different story? I took the battery out last fall, put it back in the combine knowing that it would fire up and come out of the shed for clean up and to get ready for harvest. It would crank but would not hit a lick. Upon inspection I found that the electric fuel pump was not pumping. I took it apart and found the check valve was stuck tight. Got that fixed only to find that mice had chewed up all of the fuel return lines from the injectors. Will these motors not run with out the return lines? I cracked the fuel lines to bleed them, but really could not see much fuel making it to the injectors. The engine will run on starting fluid and the return fuel is pouring out of the barbed fittings. I did not get into too long as I did not want the mess. I will get new fuel line for it and try it again.