JD 850 Question

bodywash · Dec 7, 2004

My JD 1984 850 has approximately 900 hrs on it. It starts easy, runs great, seems to have lots of power etc. However, it has a fairly loud knock which is most noticeable at idle. It also smokes a bit -- appears to be white smoke with MAYBE a touch of blue. Every few seconds it appears to puff out more smoke than usual, and I think it also makes a very light bump sound when it puffs the smoke. There is no water in the oil, no gas bubbles in the radiator. It has new injectors. Any ideas on what I should look for? Thanks

Scott

kubmech · Dec 7, 2004

Make sure your delivery valves are tight. those are the "fittings" that stick out of the injection pump.

KENSFM · Dec 8, 2004

Your JD 850 has a Yanmar engine which is known for making a fairly loud knock especially when cold, "Yanmar Hammer". I believe that the condition you are describing is normal for this engine. I would try a little Power Service in the fuel to see if it helps the smoking problem.
Ken /forums/images/graemlins/smile.gif

BB_TX · Dec 8, 2004

If it is only at slow idle, I am not sure I would worry too much. I have an '84 JD 950 with 2100+ hours. It is also pretty loud at slow idle but smooths out as I increase the rpms. Mine doesn't smoke though except when I first start it up or put it under heavy load.