Kubota D640 black smoke
 

I have a 1782 with a Kubota D640. Engine will barely run and belches HEAVY black smoke. The injection pump was faulty and has been replaced with a rebuilt unit. Injectors have been rebuilt as well. Also the throttle seems to have no effect on engine speed. I'm not sure where to look next. Any help would be greatly appreciated!
Also does anyone know where I could download a sevice manual for this engine?

First, welcome to OCC............ :Welcome2:

Don't have the Service Manual for the D640, but we do have one for the D600. It is here........... D600

Take the air cleaner out and try it. Black smoke is un-burned fuel. A restricted air filter can cause this.
Next I would question timing. After that I would start looking into compression.

Edit. Is this a turbo charged model?? A bad turbo will also cause the condition you mentioned.

First off, thanks for the input!
Been running this in a clean environment with the air cleaner off. I will pull the injectors and do a compression test tomorrow. Would like a service manual to know the specs. BTW, valve clearance was adjusted (some were way off) and didn't change anything. I'm wondering why the throttle lever doesn't have any effect? Maybe engine doesn't get up to speed for the governor to take effect?

Where did you get the rebuilt injector pump from?

Also I would need a manual to check injection timing, but the camshaft has never been touched. It is a normally aspirated engine.

Got the pump from grainfarmer.com in montana

How was it running prior to changing injectors and pump.?

Apparently exactly the same. Major loss of power and alot of black smoke. BTW, I got it given to me from a friend who just got tired of trying to figure it out. I will see it run properly again, hopefully with a little help from more experienced people! Also, got a manual for a D600 thanks to " R Bedell". It seems to be nearly identical.

sounds to me like a pumpshaft/camshaft/crankshaft timing issue or a stuck rack in the governor. Using your shop manual, go thru all the timing procedures shown for the governor to pump (rack) and if needed check all of the gear train for proper timing. You have eliminated all the other possibilities.