2020 CB pump reseal

[Shawn C]

I've been working to restore a 1969 JD 2020 which still has the original CB injection pump. The engine would reluctantly start when I brought it home, but the pump had a pretty bad leak which I could not ignore.

Long story, but I was able to source an expensive Stanadyne rebuild (reseal) kit for the pump. I very, very carefully followed every step of the Stanadyne disassembly/reassembly procedures, and of course inspected everything in the pump along the way. The rotor, head, and other internal components visually looked good. The roller-to-roller dimension was slightly out of spec, so I adjusted that according to the manual, but everything else I just cleaned and replaced seals.

I carefully torqued everything to specs as well (including the delivery valve retaining screw which seems important according to the manual), and I replaced the delivery valve stop with a new one (the manual stated to not reuse the old one).

I've reinstalled and statically timed the pump with the engine, and I think I've bled it correctly (several times at this point) following the procedure given in the manual.

I can at this point start the tractor using ether (which I don't like to do), but it refuses to start otherwise, and when it does start, it doesn't respond to throttle (won't go above idle).

When cranking, I get fuel from the lines, but I'm not getting fuel out of the injectors. I'm assuming there's just not enough pressure to pop the injectors.

I've removed the pump once already to partially disassemble and reinspect, but everything I can see looks correct. Before I remove it again, I thought I would try posting here in case anyone with CB pump experience has any thoughts.

And yes, the electric shutoff is working correctly (and I do get fuel from the lines as I mentioned), timing should be pretty close, and I've even tried replacing the injectors in case the old ones were just bad.

I originally considered trying to find a DB pump (and lines, etc.), but after talking to one of the techs at Spencer Diesel (Iowa) who insisted that the CB pump was the best pump for this tractor, I decided to go ahead with the refurb/reseal.

Any help at all would be appreciated.

 

[Al Baker(pumpman)]

Well I am no expert, but have seen my share of Charlie Brown Pumps CB. My 1st Question is did you get the Allen pin in the right
hole of the throttle control. I have been behind a few back yard I will do it myselfs and seen more than one that was tightened
into the wrong spot, then this caused a bur in the tube. Pull your control and make sue its guts spin freely. It will run like
this, just no throttle response. Al

 

[Shawn C]

Al, thanks for the suggestion. I know exactly what you're referring to, and I did try to follow that according to the book, but I'll double-check. The Stanadyne manual is pretty good, but of course being from 1970 or so, the grainy black-and-white pictures are not always clear. They also tend to over-explain things which should be pretty obvious (avoiding cross-threading for example), but they gloss over other things which are really not so obvious. I know I definitely hit one of the holes, and I'm 99% sure it's right, but that whole tube assembly seemed a little weird in the way it operates.

 

[Shawn C]

Al, thinking more about what you suggested, can you please clarify the spin freely part? If you're talking about the metering valve, then it would have to be off the tractor (on the bench) to spin this from the back end (where the governor weight retainer assembly engages). Is that the part you're thinking about?

 

[fdt860]

I think that it he is talking about the pin/valve under the throttle rack that could be stuck. I think this can be checked from under the pump.