M5 Diesel Fuel System

I have an M5 diesel with the Roosa Master injection pump. The fuel system on this machine is somewhat confusing to me, as there is no lift pump to supply the injector pump. There is a fitting in the fuel line on the pump with a line that connects to the engine block side of the pump. My guess is that is to provide a suction to the line. The filters have been replaced, and they were terrible.
when the line is disconnected at the pump, a slow trickle of fuel comes out. when everything is connected and the line is cracked at the injector, nothing.
This tractor ran great before, started good, and had little smoke. Last year, it just wouldn't start. I am probably in over my head, but i just couldnt let it go to the scrapper.
Any help would be appreciated.

Call me @ 248 770 0871, I'm sure we can get it figured out, it may need the injection pump rebuilt. The supply to the transfer pump is gravity. You could even have a plugged fuel return line.

That line is a Stanadyne/Roosa Master invention called a "filter saver". It returned excess fuel from the inside of the pump back to the transfer pump rather than through the tank only to have to be sucked back up and filtered again.

Here's a couple of photos I found on the 'net.

If the line is removed the fitting in the top of the pump has to be changed. I can't remember exactly what needs to be done at the transfer case inlet fitting.

The photos refer to a DEERE 2010 pump, but your's will be similar.

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/RoosaFilterSaver1.jpg">

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/RoosaFilterSaver2.jpg">

Here's a little more information, "cut" from another site and "pasted" here:

"The small hose with it's special fittings was called a "filter saver" and was developed by Roosa Master engineers. The idea was that if you sent most of the return fuel (already filtered) back to the pump inlet this would lessen the flow through the fuel filter and extend it's life. Two problems with this..., this increased the pump's operating temperature and second.., owners now thought that they never had to change the fuel filter. Anyhow this idea was canned, these things were removed and all the return fuel was sent back to the tank."

The pump is gravity fed? It seems as though the tank is lower than the pump inlet. My tractor has had a lot of modifications done to it, like an aftermarket filter unit, but I suppose it did work before. Is there a rule of thumb to determine when there is enough fuel flow to the pump?
I am away from home at this time but I will be going back this weekend.

Also, the jugs and heads are not original. A local mechanic rebuilt it about 8 years ago. The engine block is painted brown, but the blocks and heads are the later energy yellow. The mechanic told me they came from "a big 6 cylinder." It dyno'd at 77 hp on the pto with no smoke. I'm sure that probably does not make a difference, but is interesting anyway. I guess that is why I like these so much.

On some of these molines, I have had to fill the tank half way up to get the pump to prime.

A lot of tractors of that age did not use a lift pump with the Roosa pump. The transfer pump inside the pump pulls the fuel through the filters and supplies the high pressure pump with fuel. How can I contact you? J.

Hello Dave Ritenburgh,
How does a plugged return fuel line effect fuel delivery to the pump. The return fuel is just extra fuel, not used by the injectors, that returns to the tank right?
Guido.

If you plug off the return fuel line, It WILL stall the tractor due to increased housing pressure.

Hello David,
If you plug the return line, nothing will happen. I though the same thing years ago. A couple of system I we did just that at work.
Cummins PT pump system. NTC 335 model.
Detroit Diesel 6V 92 series engines.
Both trucks ran that way untill the test equipment we used to test fuel consuption was taken off the trucks.
So we put the system back as it was from the factory, no harm done.
Guido.

It happened to My M504 just 2 months ago, It would run for about 5 seconds and stall and I found the inlet where the return goes to the tank was plugged from mud dobbers when the tank was off. I blew out the fitting and it corrected the problem. Pump shops have told me to check for that for years.

I primed the fuel system on a D17 by leaving the supply line to the pump loose and put the hose on the blowing side of my shop vac and using it to pressurize the tank through the filler. Worked very well.