About a year ago I found diesel fuel in the crankcase but have not been able to find how it got in there.  Can someone tell me what I need to look for I finally have some time to work on it.  The S/N is 17A16035.

There is an O-Ring located between the fuel filter housing and the injector housing that goes bad. There are several past threads that discuss this problem. I had the problem with my D4 7U a few years ago. I will try to find the part number for the O-ring or some one may get it to you before I do. Try using the search tool. There is a lot of info on this problem. I believe that the seal is a 8B4967 but am not certain. I do not have any info on the D7.  There are two seals , one on the fuel tower side and one on the governor side. I changes both while I had it apart. The old ones will not look like O-rings at all because they come out very much out of shape. There should be pictures on some of the old posts. The D7 may also have other seals that I am not aware of. I have only had the problem with my D4 so hopefully some one familiar with the D7 can help. I seem to recall a post here not to long ago about the fuel transfer pump on a D7 causing the same issue? Hope I am not leading you in the wrong direction.

Bruce

check the transfer pump and replace the seals as mentioned on the injection pump. its not a expensive fix and will save the engine.

Old Magnet can you give me some advice?

Most likely culprit is a failed o-ring seal for the fuel gallery connection between the injection pump and filter housing. Part # 8B4967 (trade size -318). Requires removal of injection pump to replace. If the transfer pump seals were leaking it would show up as flow/dripping from the tell tale line that drains the cavity between the two pump seals.

Old Magnet can I remove the injection pump from the filter housing without removing the entire governor, filter housing and injection pump. Looks like there are a couple of bolts on the engine side of the injection pump that might be tricky to get out. can the injection pump be put back out of time or is it fool proof? I think all this fuel got into the crankcase when the tractor was setting for several months without being used. I want to get this fuel leak stopped and then try to start the diesel engine to see if it will still run ok before deciding what to do next which would be an engine overhaul.

If it was running when you stopped it should still be OK.
I check oil at shut off as the engine idles in cool down. Found more oil than the day before. Changed the oil, it as I was planting time and really needed it. After 6 hours looked and over full again. Took the chance and drove it a hour to put it in the yard. Payed a friend for day with his Cat to finish. At this point it was leaking without being running.

Has been 5 years (? time fly's could be more ) still running 50 to 100 hours a year. But I also have the remains of one that a guy tried to get just one more day out of that will never run again.

On the 9u D6's you cannot get it out of time. It all came off together. But a D7 could be different.

As I stated you only need to remove the injection pump. Pump timing is by offset tang at the coupling, you can't get it out of time.