I have two questions.First, Are there any likely places to look for diesel leaking into the crankase while it is parked with the fuel on. Second, How does the pressure regulator (I think that's what it is) in the primary fuel pump work? My story: I always wanted a large 2 cylinder JD since I was in high school listening to my neigbbor plowing with his new 830. Last fall I bought a reasonable 720D pony start, changed the fluids that had water in them from sitting outside, and parked it inside for the winter. When it fianlly got somewhat warm I went to start it and it looked like the engine oil was high and the fuel was lower than last fall, but the oil did not smell like diesel. Moved it a few feet and shut it off, and turned fuel off. Last Saturday, I found the oil higher and thinner, and the fuel lower. Went to start it to move it to where I would change the oil, forgetting to turn fuel on. It fired a few times and quit. Remembered fuel. Turned fuel on, but it would not start. Disconnected pipe where it goes into engine and got some flow with engine not running, so filters (which I have not changed yet) not completely plugged. Still no start, so I cranked with the line disconnected at the engine expecting more flow from the primary pump, but there was no extra pressure. Removed primary pump, noticed fuel weep hole in bottom, so I can probably rule out the privmary pump shaft seal as source of leakage into engine. I used a drill to spin primary pump, made a mess, and confirmed that it did not pump. So removed the gear cover and noticed that the presure regulator ball seat was at the top of the hole slightly rubbing on the gears. When I disassembled further I saw that the output was below the reg ball as was a hole from the supply to the output. And, the reg. ball seat, kind of a cup, moves freely in the hole with maybe .015 clearance. It looks like the ball and seat should be below the output so it functions as a pressure regulator but I can see nothing to keep it there. I thought maybe the flow should compress the spring and push it down (which would allow straight through flow to prime with the engine off, a neat idea) but I think the clearance is too much to build pressure. Anyway, since it didn't run the way it was, I used solder (easy to remove) to increase the OD of the seat to where it would stay at the bottom of the hole. Put it back together, it now pumps fuel, and IT RUNS. I should also add that I had the injector pump cover off, and bled any air out of the fuel rail, so maybe that's what really fixed it. Can anyone think of a better way to spend a Saturday afternoon!!!
| 
