help troubleshooting missing MD

Went to look at a MD this afternoon. Full of antifreeze, engine oil black. Started on gas seemed fine, not real smooth at first but has only been started a few times in the past ten years so probably needs good tune up. Switched over to diesel fine but was smoking(raw unburnt diesel). Cracked bleeders at injectors after letting run for 15 minutes and determined that number one was the problem. With the bleeder open and squirting diesel the smoke cleared up. Close the bleeder and it would smoke again. After running another 15 minutes it started popping and cleared up. Good oil pressure and fuel pressure by the guages and no noticable blowby out the breather or the oil fill. Shut the tractor down and waited 5 minutes to restart and tractor was missfiring again. Temp was around 40 degrees and I am pretty sure the thermostat is stuck open or missing as I was unable to get temp guage to move even with a pair of my coveralls over radiator. Unable to drive or otherwise load the engine due to missing parts on the attached backhoe. Should I be looking into a bad injector or a sticking valve or something else? Agreed to purchase tractor so looking for ideas for when I get it home. Thanks for your help.

Sounds like low compression on cyl #1, when it will fire when hot but not cold. Removing the fuel when cold will cause the smoke to clear on a cyl that does not have enough compression heat. If you are lucky a good working thermostat may be all it needs.

Could be a sticking or bent decompression valve in number 1 position
JG

Stuck starting valve....

It sounds like one of the change over valves is stuck open. That will cause that. Ours will do that some times. If you take the tappet cover off and tap that valve it will probably help. Give it an oil change seems to help with that. If you could go work it hard like on a plow for a day or so it would probably clear it up. They need to run daily or those change over valves will stick like that. When we used ours to feed cows every day it would start fine even at -20. Might even be the only thing that did start.

Remove number one spark plug and with decompression lever in diesel run position, hit the starter. If it blows out of number on plug hole you know you have stuck, sticky or most likely warped starting decompression valve. If it was stuck open , not likely would ever hit but if warped and leaking it would probably hit after warming up for a while. Other wise, you have low compression caused by cyl, piston , ring problems.

In addition you could pull all the plugs, leave it in gasoline mode and take a compression check on all cylinders. It will be low, as they had low compression gas running situation, but differences between the 234 and #1 would tell the story of low compression. A valve job gon too deep will sure cause the issue. recession is way important for these diesels. Jim