Put a volt meter or test light on the glow plug then turn on the key. see if the glow plug looses current as soon as the light goes out. If the test light goes out the same time then temporarily, carefully bypass the glow controller with a HEAVY wire to energize the glow plugs manually. One end of the wier is hooked directly to the battery and the other end hooks to all the glow plugs. DO NOT LEAVE IT HOOKED UP TO THE GLOW PLUGS FOR MORE THAT 10-20 SECONDS AT A TIME. See if it starts by doing that. If it has never been done by you, check the valve clearances. I fixed many a hard starting Mercedes diesels that way as the valves were tight.Thanks motorhead, I checked the GPs with my meter and all checked out ok and yes im having a hard time starting. Its acting like its 0 outside when its only 60. Now about the other (old age stuff) u mentioned....im sure i have it ALL as the tractor has over 3 thousand uncared for hours on it by the previous ownerDave