D7 47A getting air

Try leaving the tank fuel valve open when parked and see if you can see a fuel leak. I suspect that when you shut off tank valve, some fuel drains or leaks out and air enters your system. Thats what you take care of when you bleed the pumps. Or, pressurize the tank, old piece of inner tube with valve stem and hose clamp, and see if you have a leak. Could be fuel transfer pump leaking into crankcase???
Bill Walter

Thanks Bill.
I will definitely try leaving the valve open.

The transfer pump is the ONE item I didn't dismantle and go through, and since fuel pressure is always at max I assumed it was ok. On the other hand I have not noticed oil level rising on dipstick of main either.

I thought one time I saw a little diesel fuel at bottom of transfer pump where end cap bolts onto pump body with 6 or 8 bolts.

Probably fired this machine up 20 times before this situation showed up. Again, seems related to fuel tank level but that doesn't make sense to me.

One way to check is disconnect and cap off all but one fuel injection pump. (3/8" JIC caps). Hook up one of those hand vacuum pumps with the fuel valve turned off at the tank. If it will hold reasonable vacuum the problem is most likely at the injectors. I'd be suspect of those old brass fuel shut off valves, they are not exactly bubble tight.

Thanks OM.

All 4 injector nozzles are new.

Both brass valves at bottom of tank sweat a little fuel. I just assumed it was weeping past the packings and not a real big issue. Could this be my problem?

I think you will get more milage out of pressurizing the tank than pulling a vacuum on the fuel system. It's hard to detect a tiny vacuum leak, but relatively simpoe to see a fuel seep.

I would suspect a leak some where high on the tractor, so it's above the fuel level when the engine is shut down. Or could be it's a leak that lets fuel as well as air in.

It's quite possible that you would not have to bleed it if you left the fuel valve on..............but that could lead to other problems since it seems to have a leak somewhere.

I investigated closely today and the piece of copper tubing that makes up onto shutoff valve was not real tight. Someone put a short piece of copper tubing onto shutoff valve, then a short piece of hose goes from that to the long line that runs to primary.

I had replaced hose and clamps and made sure that was good a long time ago, but the copper tubing has a rubber compression fitting where it makes up to shutoff instead of a copper ferrule, which I prefer. Maybe that will fix it, if not it needs doing anyway.

Was the original a 1 piece steel line?

Original line was steel....3/8" hydraulic hose and some fittings makes a nice replacement unless you are going for show.

Original line had silver soldered ferrules. The rubber seal is a cobble fix.

Put the correct fuel line on. Its drawing air into the system.