Fuel system losing prime

Have you noticed any change in engine oil level?

Hi OM.... Yes I did see quite a drop after discing with it for about 30 minutes a few days ago... then yesterday after it sat a few days it wouldn't start until I bled it... then I disced for another hour and it didn't seem to use any oil.

Try loosening the fuel cap on the diesel tank. OZ suggested that to me. His thinking was that it was building a vacuum while running and after the main engine was shut off the tank was sucking the fuel back to the tank.

John

Hi Wayne,
I was thinking the other way.....that you might have a leaking seal between filter tower and pump housing that would allow air in and fuel to leak into the sump with a corresponding rise in oil level.

John,
It would seem that you would have to have an air leak in the system to allow draw back/venting to the tank. Just putting a vacuum to the liquid would not establish flow.

Hi Wayne.........I was having a similar problem a few weeks back and my problem stemmed from the fuel transfer pump. The guys here guided me through the process and along with a couple other things fixed the problem.
That may be something to look at....
Have a good day....Bill

Thanks everyone for your suggestions... I'll investigate further and report my findings. Wayne

Well the tractor started today as it should.... no priming required... although it had only sat for about 36 hours since I last ran it.
The vent on the fuel tank is clear and passes air... there are no visible leaks in the system... there does not appear to be any diesel getting into the crankcase... the transfer pump puts out 10 to 15 PSI depending on engine RPM, so I'm thinking the seals are OK.
I'll let it sit for several days and see what happens.

Like Cysco said, watch the transfer pump for problems. If the "drains" from the pump are not open, any seepage goes right into the crankcase.
Last winter I drained about 20 gal of fuel into the crankcase on the D47U caused by a leaky transfer pump and a plugged vent pipe. It can also leak from the injector pump into the crankcase if that vent pipe is plugged and the pump leaks.
Sure made it look like the ole D4 was manufacturing oil while it sat there!! 😊 😊 😊