Okay, back to my m4900 injectors. First, thanks for the response. Got injectors out. Little rust on the tips. Cleaned them as best I could. Tractor hard to start but eventually ran. Rough. My question is this. All 5 on the injection pump look the same with the lines off. Fuel is good. When tight, runs rough. Cracking lines. 1, 3 , 5, no difference. 2 and 4, engine slows down. Re tighten, engine speeds up. Is there an adjustment On the pump at the fitting below the nut. It seems a bar against knurls stops them from rotating. Thanks in advance.