JD2640 smoking

[K.Daddy1]

I just had the head reworked for suspected blown head gasket. (Wasn't overheating-just warmer than should be) The tractor ran fine before removing the head. While the head was off, I had the injectors sent off to be cleaned and was told the injectors were 800lbs low on pressure. They sent me re-furb'd injectors-to make a long story short. The tractor is back together but smokes when started, increase the rpm about 1600-1700 rpm the engine is struggling to get there, but smokes really bad. The return line is not stopped up. The injector pump wasn't removed-so it's not the timing. What could it be??

 

[Walt Davies]

I would suspect the new injectors as that was the only thing that you changed that would cause your problem.
Walt

 

[buickanddeere]

Put those injectors on a test stand and check the spray pattern & popping pressure. Don't take them to the same shop or tell the shop where they came from.
Sounds like they were incorrectly rebuilt or they were just cores that were never rebuilt.
New head bolts are required as used fasteners will not give a reliable re-torque. Particularly if you suspected seepage prior.
I have to suspect the decision to change a head gasket when the engine was running fine and was only running warm..................
Odds are the rad is plugged on the outside with oily dirt. Plugged on the inside with scale because somebody added tap water rather than distilled water. The fan belt/pulleys are glazed/worn. Or the stat is getting balky being about 25 years old. The temp gauge could be out of calibration with years of vibration and exposure to weather.
As for an engine being too hot? With a pressurized cooling system with 50/50 mix. Unless you tractor is a supercharged or turboed pulling tractor running on gasoline. 195-210F is the ideal operating temp for a hard working engine. An engine at part load putting around, doing loader work etc is better off running 210-220F.