Deere 2640, think injector pump croaked

Im pretty handy with gas stuff but I know absolutely nothing about diesels.

We have a deer 2640 that I use 8-10 hours a year for Bushhogging.

Bought it about 10 years ago and it has been a good tractor. I have changed the hydraulic fluid and cleaned filters, found that a mid 80s jeep CJ alternator will fit with a simple pulley swap, and of course oil and air filter changes.

But a couple of days ago when Bushhogging, The tractor started bogging down. I switched to a lower gear and it continued to bog. Throttling up made no difference so I knew something was wrong. I started back towards the shop and it eventually died. It will crank right up and run for about three or four seconds and then die again.

I changed the fuel filter yesterday and the fuel looks good. It looks like I can also crack the return line on top of the pump the bleeding the air out of the pump itself, but from what I found online it sounds like that plastic ring might have given up the ghost and clogged the pump.

To local people I trust have said that it has to be calibrated so its not something I should attempt to do on my own.

So my first question is, is there a way for me to definitely determined that the injector pump is the problem? I would hate to take this thing off and take it somewhere for a rebuild only to find that it was something else causing the problem

Second question is, I understand these are times with the engine. Local diesel mech said that it should be keyed and that the gear stays in the engine so that as long as I dont pull the shaft out of the engine it will stay in time. Can anyone verify that on this particular model?

It also looks like there is a solid metal piece centrifugal clutch(?) that will replace the plastic ring that causes these problems. Does anyone have a link to that?

Ive done timing belt on my Honda cars, and I rebuild ATV engines down to the crank all the time, so Im not afraid of wrenches. I just like to do my research before I tear into something Im not familiar with.

I believe that has a lift pump, looks just like the fuel pump on a gas engine, tests like a gas pump would test.

Check that, see if it is delivering fuel to the injector pump. If it is, good chance it is the injector pump failing.

Yes it is timed. Some will only go on one way, some have to be timed. Before taking it off find the engine timing marks and look at where the pump drive is before disengaging it.

Someone will be along with more details.

Before you assume the worst, are you sure you have bled ALL of the air out all the way to the injectors? You really need to know the proper bleeding procedure for that tractor.

Hello Jeep welcome to YT! One thing you can do to check if the injection pump is the problem is loosen the little plate with two screws on the side of the pump so it can leak fuel. Maybe loosen about as much as a faucet would flow in a continuous stream but not so slow that it turns to individual drips. Then start the tractor and see if it will continue to keep running. If so the break down of the governor ring is likely your problem. You mention loosening the return line on the pump, the fitting that the return line screws into is a check valve to help hold fuel in the pump when the engine is off. Pieces of the governor ring get in it and plug it. When pressure builds up in the pump housing the delivery plungers cannot move out to pickup the proper amount of fuel so the engine quits. If the engine runs fine with the plate loose likely the governor ring is the issue. You can also pull that plate off and see if there is debris in there that looks like coffee grounds, which also confirms the ring is bad. If you pull that you might want to make sure you have the tractor in a place where you want to pull the pump off otherwise it may require a bit of bleeding of air to restart it. I really should not tell you this but as a TEMPORARY FIX you can unplug that check valve or even go so far as to knock that check ball out with a punch and your tractor will then run fine. However, given time, parts will be hammering against each other metal to metal in the pump and running it long term like this can do additional damage. I do know that in some cases on Deeres the info about the gears staying in time is correct, but I cannot say for sure if that applies to your model someone else will have the answer that.

The Roosamaster pump on your tractor is not real particular about air bleeding. If the tractor has run 20 or so seconds and starts right back up after a couple minutes rest the system is probably bled well enough to continue running. I should also add if you so choose there are a couple of guys on here that you can ship your pump to and have it rebuilt. They chime in here often on pump issues. I have always heard good things about the quality of their work and the economical prices. Just post back here if you want to go that route and I will get more info for you.

There should be a small plate, held on by two screws, on the side of the injection pump. Loosen the screws a bit to let fuel leak out. Start it and run/try it out a bit. If it runs better/good with the fuel leaking out, it is a sign your pump needs a rebuild.

Yes, this test with the side plate is what determined mine was bad. I too am not very experienced in diesel repairs. Dieseltech on this forum helped me greatly with repair of my pump- in fact he was the one who rebuilt it! If he chimes in I would value his advice.

If the lift pump checks out, remove the return line and the fitting that goes into the pump. Then it may run. There is some sort of a glass ball in the fitting.I broke mine out to get it to run to the shop

As others have said try loosening the screws that hold the timing window cover. If it runs then, your return line is plugged. Given the questions you are asking, it would be best to have the pump serviced by an experienced individual.

As to R&R the pump, under that same window there are two rings with a line scribed across them. That is your pump timing mark. Rotate the engine in its normal direction until the marks line up. You can then remove the pump and have it serviced. So long as the engine doesnt move, you can line up the marks on reinstall and your timing will be correct.

Wow thanks for all the replies!

Yesterday I actually removed that plate under the two screws on the side to see if there was debris in there. There was not but quite a bit of diesel ran out and after I did that it wouldnt even fire for a few seconds before dying like it did before, so Im guessing that I emptied the pump completely out of diesel and it needs to have the air bled out of it now.

I need to check that lifter pump before I do anything else to the injector pump. Best way to test that? Can I just remove the line going into the injector pump and see if diesel sprays out of that line when I turn the tractor over?

In my opinion if it gives a good strong squirt of fuel every time the cam pushes its lever it is probably not the problem. And yes now that you said that you removed the plate the fuel did empty from the pump. I believe the lift pump may have a manual priming lever on it. When you move it you should feel a good resistance most of its stroke. If not the engine stopped as the cam lobe depressed its
internal lever. You have to bump the starter to let the cam release it so you can stroke the manual lever to prime it. There should be a bleeder to open on the upper part of the injection pump housing that you open and pump the manual lever until there is only fuel and no air coming out.

Thank you! Ill try that tomorrow and report back

The Stanadyne/Roosa pumps have no bleed screw, and main housing is self bleeding. DO NOT remove the return ball/spring inside the return fitting and keep running engine thinking all is well, or you WILL seize the hydraulic head AND break the drive shaft when the retainer pins shear off. Have seen that happen several times in forty five years and counting of injection pump repair.

Hope yall are still with me.

Was too wet to get back to where the tractor died with any hope of towing it back to the shop, so been waiting on it to dry out a bit.

Plan is to drag it back to the house today and see what I can find.

Got the tractor back to the house.

Plan is to remove the inlet line going to the injector pump, crank the tractor over and see if the lifter pump is working.

Assuming it sprays diesel everywhere, I'll hook that line back up, and loosen the return line on top of the injector pump to bleed the air out, see if the tractor will start that way.

Does that sound correct?

I checked locally on pump rebuilds (well, locally as in 65 mile drive to Memphis) and neither place was willing to build a pump with a solid weight cage instead of a flex ring, and both said it would be several weeks to rebuild one.

Assuming it does end up being the pump, I'll likely reach out here on the forum. Who all here rebuilds these things?

One can check lift pump fuel delivery by loosen line at in pump or simply opening bleeder on fuel filter & pump handle on lift pump. When attempting to pump lift pump handle if no resistance is felt bump starter so as to rotate camshaft off high lobe that powers lift pump & manually move lever.

If it is a RoosaMaster rotary pump, starts and runs for 20-30 seconds, dies, and can be restarted in a couple minutes, and this continues, most likely the governor ring inside the pump is bad. If you remove the return line check valve assembly from the pump top cover, and find what looks like coffee grounds, this is a sure sign the ring is bad.
Do not remove the check valve completely, as some have done. The injection pump needs a certain amount of internal fuel pressure to properly fill the pump injection cavity., and provide the proper quantity of fuel to the injectors. Fuel lubricates the internal parts, and minimal fuel can cause major damage to the close-tolerance parts.
The pump has to be removed, disassembled, and the part replaced. A flexible ring is needed, as this is a variable speed application. Something to do with the governor and stresses to the pump components as engine speed varies. A generator, a fixed-speed application, can use the solid ring.
Proper tools are needed for repair. Most pump shops will NOT calibrate the pump, or even put it on their machine, without a complete dissassembly and rebuild. Has to do with the potential of debris from inside the pump ruining their very high-dollar calibration machine.
I have replaced a couple of governor rings, but it is a pain without the proper tools and fixtures. zuhnc

Finally had a chance to get the tractor back to the house last weekend and got it fired up after work today.

I used the lifter pump to bleed the system with the return line off of the injector pump.

Once I got the air bled the tractor fired up and ran fine with the return line unhooked from the injector pump.

No fuel was coming from the return line with the tractor running.

So from what I have read here and elsewhere I think it is safe to assume that the injector pump plastic ring has come apart and the injector pump needs to be gone through, correct?

Remove fitting(item 16) that contains a check valve & if it's clogged more than likely drive ring in IP his deteriorating.

This post was edited by jeepwm69 on 06/22/2022 at 07:17 am.

Pulled that fitting off and it was indeed full of goop, so I guess that means my plastic bit has disintegrated.

Now to find someone to rebuild it.