Case 4890 injection pump/governor issue?

Hello there. We have a 4890 Case with a dozer and this winter we have put at least a 50 hours on it pushing snow. This last while it started stalling out just as if it is running out of fuel. First we installed a new set of fuel filters, We installed a new fuel line, changed primer pump. Funny thing it runs great for about 1/2 an hour, then problem only begins once engine is warmed up. I installed a pressure gauge after the filters. 12-16 psi when running. When it stalls there is still 5-10 psi there but it will not restart. A couple pumps with the primer and then it fires right off. I do notice when I am pumping the primer there is a metallic clunk that comes from the governor end of the injector pump. Then it will fire right up. It is almost like the fuel shutoff is being 1/2 pulled. If caught before it stalls and you push the throttle WOT. It sputters and misses a bit (like you pulled the shut off out 1/2 way)then takes right off to high idle. Because this tractor has done a lot of snow plowing in the past. The governor gets quite a workout. Push/ backup push backup. I am starting to think that this is not a air in fuel issue but rather something in the governor is coming apart. When it is sputtering there is no throttle lever response to come back to idle until it finally does take off to high idle. Then I can always bring it back to idle.
In my 15 years of pulling wrenches this is a new problem I have not seen before what are your thoughts? In the spring and summer this is our tillage tractor. to in fall running the 1682 combine for harvest.
Ranch

I should also note that the governor response is very crisp and very fast when the engine is running fine. This works well on the pull type combine.
Ranch

Have you checked in the tank for any obstructions/dirt,ice or slush. Sounds more like a plug in the supply than pump. Since you say when it acts up it only has 5-10 instead of the 15-20. Any hoses that could have a flap or sucking flat to restrict. After all this is an older tractor.

I agree with an obstruction in the tank moving around. The timing of the start of the problem could be length of time pulling fuel instead of temperature. When it stops running the material blocking the suction screen drifts away. Your problem has come up here many times. You need to drain and remove the tank and flush it to eliminate this problem.

My vote is fuel supply issue, not the governor. The Bosch RSV governor has a pair of heavy flyweights that will sometimes make the noise you describe, that's normal. If the plunger control rack was sticking, it would not run fine at times. Check all the suction side supply lines, getting ANY air in the system WILL cause trouble too, and there may not be any fuel leaks. Also possible to have hoses fail inside that restrict flow too. Could also be a problem with the injection pump overflow valve, they can fail over time. Also check the fuel tank vent, there's no fuel out if no air gets in. If restricted, that can cause trouble too. Neighbor's White 2-155 would run fine about 1/2 hour, then slowly die. When the fuel cap was removed it pulled off hard and there was a WHOOSH heard as air rushed in past the cap. Tractor ran fine with the cap loose.

Had trouble on a Case tractor with a Bosch pump trying to keep it running. Plunger on the transfer pump would stick...had some condensation in there causing it. Maybe with your winter use you have the same problem. Took it apart here and cleaned all up and replaced the o-ring in the plunger and good ever since.

I'm not sure what pump is on this on as it has the Scania engine in it. May not be a bosh pump.

It's the Robert Bosch inline PE 6P with the RSV governor used on the Scania engine.

I pulled the pump overflow valve. I see other folks have been in here before as there is a helicoil set in the housing that the valve screws into. With the valve I can suck air through it once in a while. It is as if the valve does not seat properly all the time. Now to search for parts. Part number?
Ranch

That heli coil is factory stock to reduce the M16 x 1.5 thread down to M14 x 1.5 thread. I have a parts pump but not sure if it has a good overflow valve on it.