720 Diesel smoking problem

[Anonymous-0]

I recently purchased a 720 Diesel ES and I'm having a couple of issues with it. First off, when I had it delivered, it seemed to run real well and everything seemed to be in good order. After a few days, I noticed it smoking a little more than I thought it should. It was mainly white but would have a slight blue tint every once in a while. It smoked slightly at idle but it would belch smoke when I throttled it up. I thought maybe it had a little gunk buildup from sitting for a while. The gentlemen I bought it from hadn't used it very much. After putting some load on it, the smoking seemed to increase. Someone on the farm here used it to pull some wagons and he said it spat oil up through the exhaust and some blue smoke was coming up. After I tried it out, I didn't get any more oil but it still is smoking pretty good. I brought it into the shop and decided to investigate. I took the injectors out and cleaned them out. I also noticed that the oil pressure was up too high, so I tried to adjust the pressure, but the regulator will only turn so far out and it seems to jam and the pressure didn't change much when I adjusted it. I did an oil change and cleaned the air filter out, but its still smoking some. Does anybody have any other thoughts. My next thought was the injectors need to be throughly serviced as well as the pumps, but that doesn't really explain the oil. The smoke does have a slight blue tint to it sometimes, otherwise its white. Does it just need to be run hard to clen it out a little bit from sitting. I don't know the history of the tractor that well, but the previous owner seemed to have not used it very much. Can anybody shed some light on the next best move. I would like to get the tractor running well cause I wanted to use it this fall. The good thing is it starts real easy, but one other issue is that it dies when the throttle is pulled back, even before the stop knob is out. Is that just a simple adjustment. I bled the filters to see if they were clogged. they seem alright. Sorry for the long message but I want to try to explain the problem so I can get the most accurate advice as to how to remedy it.

 

[Anonymous-0]

Check to see if you are getting diesel fuel in the crankcase. It can get there due to worn out seals in the fuel transfer pump or injector lines in the valve cover. After that could be worn valve guides, piston rings, cylinders worn out of round. If it starts good it must have decent compression. I would check the crank case oil for diesel first then work it hard and hope that helps. Oh by the way check the flywheel for tightness just because they get loose and tear themselves up.

 

[A. Red]

Before doing anything drastic make sure you have a clean air and FUEL filter.Improper air/fuel mixture can cause a lot of smoke.

 

[Anonymous-0]

JD630...generally on the two cylinder diesels the white smoke is an indication of low compression. The blue smoke is a sign of worn / broken rings, pitted cylinder bores or excessively worn cylinder bores. The black "slobber" is a symptom of all the above. If you let it idle for awhile and then crack the throttle..if you get blue smoke instead of black smoke ...it needs some internal repairs. Also, check your radiator for any signs of oil or exhaust residue. If it's there..could be a bad head gasket or cracked head.

 

[Mike M]

In addition to the other advice I'd go ahead and double check the timing. Can't hurt,might help ? but likely it is just plain worn out which is all too common on these. Very seldom do they get a complete overhaul.

 

[Anonymous-0]

Starts easy, smokes, and oil up the stack. No history of being worked recently, on the contrary mostly ilded.

Put clean filters in it and service the air filter. Hitch it up and work the snot out of it, literally. the cylinder walls are varnished up and not sealing well.

Pretty soon it will not start well.

If this diagnosis is correct you will find power growing, less smoke, and the oil up the stack will go away.

 

[jd820]

I use to own a 820 diesel with a similar problem. It sounds to me like the delivery valves in the rack are not working properly. The if the tractor is not burning any oil then it is pushing to much fuel into the combustion chamber. the only way to solve that problem is pull the rack and have it tested. As for the tractor die off when the throttle is pulled back it sounds like the linkage is out of adjustment. Let me know what happens.

 

[Anonymous-0]

I appreciate all the tips. When I changed the oil, I checked it to see if it had any diesel in it. Didn't detect any at all. I think the easiest course of action is to probably the run the snot out of it idea and see where it goes from the there. I've got a field to disk real soon so I'll think I'll hitch it up and see if I can at least put a little load on it and see if it improves. I've got a 520 crying for a major overhaul and that's on the docket before this puppy so if I need to take things a step furthur I might have to wait a little while. Although the timing might not be a bad idea to double check. Any other thoughts, let me know.

 

[Tom Weber]

Have an 820 that did that. Found bad Head gskt caused from last "overhauler" not installing the 3 head bolts that go in from the rear of the head. New gasket, proper bolts and torque and all ended well.