Tractor Repair: Tractor runs rough and smokes a lot

Question
Hi Guy's I got a(1980?) 1290 case tractor a few months ago and it run like a dream! I only use it 4 or 5 times a month
for moving fire wood in my yard..It sat for a couple of weeks and one day I changed the oil and filter and also the fuel filters!!I bleed the lines and fired it up and it smokes (nostly white smoke )a lot,It idles fine(lots of smoke ) but when I throtle up It runs rough and smokes worse.I have taken 5 gallons of fuel from the botton of the tank in case of water and no differents . I have re -bleed the lines several times and It doesn't help!I also open the injectors one at a time and they all act the same,the engine shackes a little more and smokes a little less and when you tighen them up again it goes back to lots of smoke ..this sounds crazzy but I hope you can help??

Answer
 Not sure, but it sounds like you're saying this problem only started after changing the fuel filters.  It sounds more like the injection timing is late by the way it acts.  I worked on one a few weeks ago that someone had accidentally put gas in it instead of diesel fuel and it ran like yours and smoked real bad.  Remove the fuel filters again and check that the gaskets on the fuel filters are installed and seated correctly.  I have seen gaskets installed wrong and it allowed it to suck air into the fuel.