Volvo Penta MD2030B governor problem

[SandMan874]

Hello,

I’m writing this because I desperately need some assistance with a Volvo Penta MD2030B which is installed in my sailing yacht.

First off, let’s start with the basic. The engine was installed in 1995, but since then it has only accumulated about 500 running hours. About 6 years ago, the boat was laid up on shore for a rather lengthy accommodation rebuild which finished earlier this year. Before re-launching the boat, the fuel injectors were cleaned and overhauled, and the glow plugs were cleaned and tested.

I can mention that one fuel injector was pretty gunked up, while the other two were only “normal” dirty. This probably explains why the engine was a bit slow to start, normally starting first on two cylinders, but this has now been fixed.

Now onto my current predicament. I’ll divide this into numbered sections, if there are follow up questions, or suggestions.


1.
When I first started the engine again, it would immediately increase the RPM to about 3000, despite the throttle being set to the idle position. It was also impossible to stop the engine with the stop lever on the governor. The only way to stop the engine was to loosen the connections on the high pressure fuel pipes.

In order to troubleshoot this problem, I tried to dismount the fuel injection pump. The pump was quite difficult to remove, and this was later found to be caused by the sliding control rod being rusted in place. In addition to this, one of the fuel pump plungers was stuck in the high position. I’ve been told this can sometimes happen as old diesel dries out over the course of many years. The fuel injection pump was then serviced at a local company.


2.
With the recently overhauled fuel injection pump reinstalled, I made another series of attempts to start the engine. However, now the engine will start, and immediately increase the RPM to about 3600. This is the maximum RPM for the engine. As before, it is impossible to stop the engine with stop lever, and I must loosen the high pressure fuel pipes to starve the engine of fuel.

When turning the engine on the starter motor with the high pressure pipes disconnected, the injection pump is still delivering fuel with stop lever fully engaged.

After talking with an “expert” (VP Service Center) on the phone, I have dismounted the fuel injection pump again, and I am in the process of looking into removing the timing gear housing to gain access to the centrifugal governor.
This is not a step I want to take, as the engine bay is very small, and I fear I will have to lift the engine out to be able to do this properly.


3.
But with the fuel injection pump removed today, I also tested the arm connecting the pump control rod to the governor. With the throttle in idle, the arm is in the fully aft position (100% on the injection pumps). The arm is being held in this position with a spring, as it can easily be pushed forward, but slides back by itself. Moving the stop lever pulls the arm forward about 1,2 cm. This is the same amount of travel as on the injection pump control rod, from 0% (fully forward) to 100% (fully aft).

I'm hoping there may be somebody in here who have had similar issues, and can give me some tips. Like I said, removing the timing gear housing to gain access to the centrifugal governor will be a nightmare.


Anyway, a few questions that maybe gets the ball rolling:

4. If I understand the working of the centrifugal governor correctly, I presume that on a stopped engine, it will always push the injection pump control rod to 100% ?
Since 0 RPM is lower than idle speed (i. e. 1200 RPM), the governor is trying to increase the amount of fuel to the engine.

5. When mounting the fuel injection pump, the connecting arm to the governor has to be pushed slightly forward (about 5 mm) to hook onto the control rod. Is this normal?
Since the arm needs to be pushed forward, this limits the remaining travel when activating the stop lever to about 7 mm. This is not enough to push the injection pump control rod to 0% to stop the engine.

6. The "expert" I have spoken to about the issue claims this must be a problem with the centrifugal governor, maybe a weight or a connecting arm has become "stuck". However, in my head this would only make sense if the stop lever would function as normal. Or am I in the wrong here?

7. Is it possible to assemble the fuel injection pump incorrectly (i. e. length of travel of control rod), or is this sort of idiot proof?


Really hope there is somebody with a few tips or tricks up their sleeve. I'll be immensely grateful for any and all insights or suggestions, even wrong ones... :-D

SandMan874

[DougR]

OK....Basic 2030 governor operation....When the engine is running, there is a delicate balance going on between the governor weights and the springs found in the injection pump linkage. The governor weights are mounted on the front end of the cam drive gear and as the engine RPM increases, the weights expand out from centrifigual force and at the same time they push a sliding regulator sleeve on its shaft in a forward direction, pressing against the throttle linkage. When you increase throttle speed setting you move the injection pump rack toward more fuel by increasing spring tension on the linkage. Initially the fuel rack moves to increase RPM, but then as the speed increases the governor weights move out, causing the regulator sleeve to counter the spring pressure and come to a balance at the requested higher RPM.
If there is some reason that the governor weights can't move, or the sliding regulator sleeve can't move, then there will be no counter force against the spring pressure and the revs will go to max.

Addressing your questions:
- There is a small light spring in the linkage which is there to cause the linkage to move into the "run" position whenever the engine is off. Without this spring, if the throttle is at idle and the engine was stopped with the stop lever, the linkage might not return to the run position and therefore not start. So....its normal for the throttle linkage to be toward the run or maybe even high fuel position when the engine is not running.
- If you were to start the engine with the throttle say in the 1/2 fuel position, the linkage springs will infact move the pump rack to the full fuel position. When the engine would start, the RPM would head for full throttle except that the governor weights would almost instantly expand and press the linkage back against the spring pressure until the RPM stabilized at the 1/2 position.
- When you activate the stop lever, you override all spring pressure and push the linkage, and hence the fuel rack, all the way to the no fuel position. Whether you can determine if this is adequate by measuring, I don't know....

- It seems to me that there are two, probably interconnected issues....one is that the governor weights or the sliding regulator sleeve are not moving, perhaps locked by corrosion. This would result in the engine running at high rpm but unable to come back down. The other is that the stop lever can't control the linkage either, and that's unusual....perhaps indicating a pump problem.

What I think I would do is install the injection pump back in the engine and hook everything back up. Then remove the plug on the rear face of the block just to the rear and below the injection pump. This will expose the rear end of the fuel rack. You should be able to see the rack, perhaps with a mirror, and also press on the rack with a small rod or screwdriver. The rack should move freely. This threaded hole is where electric stop solenoids are mounted, and they act directly on the end of the rack. You should be able to see movement of the rack when you activate the stop lever. If the engine is running, pushing forward on the end of the rack will control RPM, and if pushed far enough forward should stop the engine. If you can control rpm by pressing on the end of the rack, but not with the throttle lever, then the front cover needs to come off.

Hope this is helpful

DougR

[SandMan874]

Now this is more like it. Thank you very much DougR.

I will test your idea on Friday.

I'm also thinking it should perhaps be possible to disconnect the governor arm from the fuel rack and remount the pump without it. Maybe small gauge wires can be connected to both the fuel rack and the arm, and then run the ends out of the plug hole you mention.

By directly manipulating the fuel rack, I should be able to test if the fuel pump delivers fuel even in the 0% position when turning the engine on the starter motor, or if it indeed shuts off.

It should also be possible to start the engine and manually control the fuel rack. (Very carefully of course) By allowing the governor arm to run freely (connected to my fingers with a piece of wire), I guess this arm should also display movement, depending on the rpm of the engine. This will allow me to determine if the centrifugal governor is moving this arm at all.

Anyway, thank you so much for your excellent explanations and suggestions.

SandMan874

[SandMan874]

Since I last wrote something here, I have done a few more tests on the engine. First of all, I disconnected the arm connecting the governor to the fuel injection pump, and replaced it with a bit of copper wire running put of the plug on the rear face of the engine block. (Where I believe a stop solenoid might be mounted?)

When turning the engine on the starter motor, I can confirm that the pump does indeed regulate from 0 to 100%, with 0% being the fuel rack in the fully forward position.

After a long and grueling effort, I have actually managed to remove the timing gear housing. So the entire governor mechanism is exposed.

First off, the weights on the end of the camshaft are in pristine condition, and move with a light touch of a finger. Same for the control sleeve on the end of camshaft. All the arms mounted inside the timing gear housing are also in excellent condition, and moves freely when manipulated with a finger. So the short story is that I can´t find anything wrong with the governor.

The only thing that looks a bit puzzling to me is the plate on the arm where the stop lever pushes the fuel rack to 0%. It is not a 90 degree angle as one might expect, but instead a oddly bent angle downwards. Does this look normal?



I tried feeling how hard it is to bend this plate, and in my opinion, it takes a bit of force to bend it.

Note that in the picture, the weight of the arm pointing up is holding the arm close to the minimum position, and the starting spring is therefore stretched out. The effect of the bend in the stop plate is that the travel length of the connecting arm is smaller than if the plate had been bent at a 90 degree angle.

Apart from the odd angle of the stop plate, I can´t find anything else wrong with the governor system.

SandMan874

[DougR]

- when you activate the external stop lever, does the internal stop lever arm press the linkage all the way to the "no fuel" position? If not, maybe the slightly "bent" linkage as marked by you, needs to be straightened slightly. (But I agree....how did it get bent?)

- are the two halves of the main linkage, the one connected to the external throttle arm and the other half pivoting on the same shaft, free to move independent of each other? They should be...

- the sliding regulator sleeve, which is mounted on the camshaft, presses on the main linkage via the "oval" pad which is seen spot welded in the lower center of your photo. Normally this contact pad shows a polished spot on its surface where the regulator sleeve rubs.......but there is no polished spot on the pad in this case, which may be an indication that the regulator sleeve isn't actually pushing back against the linkage springs. If that's the case the governor weights can't really control the rpm.

DougR

[SandMan874]

Hello DougR,

1. Well, the internal stop lever does move the linkage arm to what is currently the stop position. (When the stop "plate" touches the pillar underneath it)
However, when looking at the fuel rack through the removed plug, as suggested by you, the fuel rack is NOT in the fully forward (stop) position. So the travel length of the linkage arm is not enough to move the fuel rack all the way to the no fuel position.

2. Yes, all parts of the linkage are free to move about easily. I can also see that when I add throttle using the external throttle arm, the other half of the linkage would be pressing against the control sleeve of the centrifugal governor. The more throttle I add, the harder the main spring presses against the centrifugal governor sleeve.

At the same time, there is also a bit of play between the linkage arm and the second big arm of the governor. (the one the control sleeve presses on) This can be seen in the area of the second spring, next to the starter spring. I believe this is as it should be.

3. The end of the control sleeve is a hardened steel ball which can rotate freely, so that might reduce the amount of visible wear on the governor contact pad. The engine has also not had more than 500 running hours on it, so I'm unsure how much wear would be visible. But I will clean off the lub. oil and check if I can see wear marks.

Thanks a lot for your input.

SandMan874

[DougR]

OK, all sounds good, but we have to ask " what happened to cause loss of stop function and also loss of throttle control" while the engine was in storage?

It seems to me that the only possible thing is somewhere corrosion has gummed things up.
A couple of things to try:

- Checking stop function....move the external throttle lever, to say 1/2 throttle position and the main governor spring will have decent pressure against it from the sliding sleeve. Now WHILE HOLDING THE THROTTLE LEVER IN THAT POSITION, activate the stop lever. The stop lever should be able to move the pump linkage arm all the way to where the stop plate touches the aluminum pillar. The way this can happen is that the small start spring and the other small spring can stretch and the pump linkage arm slides along the slot in the main linkage. So when the engine is running at a given constant rpm the main linkage and its heavy spring and the sliding sleeve are locked in position by the throttle lever and governor weights. But activating the stop lever can still move the pump linkage arm because the linkage arm can slide in the small spring loaded slot. Can this sliding happen? You indicate in #1 below that the stop lever goes to "stop" but the pump doesn't .... Either the linkage can't really go all the way to the pillar because it can't move enough in the slot or maybe the pump rack is out a tooth on the plungers. ( this would have to be rechecked by the pump shop.)

-RPM control- the sliding regulator sleeve needs to be able to slide freely along its shaft.....you should be able to easily slide it and remove it from the engine......
Likewise with the sleeve removed from its shaft, all four of the governor weights should be sloppy loose and able to move from completely closed to completely open with little effort. Something is preventing the governor weights/ sliding sleeve from being able to push back the main governor arm to its low rpm position.. Maybe the main governor arm/linkage has gotten gummed up on its shaft and doesn't want to move all the way back to idle. Perhaps the main governor arm mounting shaft should be removed from the case and cleaned up. I recall that it's just an O ring seal in the case.

DougR

[Mbass]

Thank you for the thread Info I am hoping the 2002 fuel system is similar my engine was also not used for an extended time and the throttle and governor do not seem to be working. Nor the shut off any help would be greatly appreciated. The throttle has no effect on engine speed. Mike

[skipperpete]

No , the plate in your photo of the stop linkage should be at 90°. Also, both of the springs in the same photo look to have been distorted.
The injector pump has a stuck plunger and needs to be un mounted and taken to a fuel injection technician for repair. The difficulty is that the fuel rack pin has to be moved a bit to lift out the pump and because its seized that might be a challenge. A word of caution when you refit the timing cover, take great care to locate the lube oil pump roll pin into the matching hole in the timing cover. You were very lucky the rack wasn’t stuck at full delivery, even on only 2 cylinders your 2030 could easily have self destructed.
Get a quote for the pump repair and weigh that up against a recon pump from Parts4engines UK. £600[emoji33]
Oops, I just re read your earlier post and noticed that you already have had the pump out so maybe you only have the stop plate and springs to fix. The plate was bent possibly because of an earlier attempt to free the rack using the stop lever during the overspeed.
Hopefully the rack now moves with the slightest touch and all the plungers return to the bottom of the stroke when depressed manually.

[sailorphil9]

I have problems with a Kubota genset and I suspect a failed governor spring.


A couple of points which are of general relevance that I have learned during my investigations:


1. If on starting a diesel engine it 'runs away' to full or higher revs (a physically dangerous situation as it can throw mechanical parts like shrapnel) the quickest way to stop it is to cover the air intake (so I have been told).


2. If a diesel engine had been standing idle for some length of time, then waxing can occur in the governor mechanism (another poster has suggested a sticking mechanism).

[Mbass]

Mine was not running away but initially stuck at about 1200-1500

[parkstone bay]

Not an answer - but huge sympathy! I had a similar issue on a Bukh 24 and it took a skilled mechanic over half an hour to adjust the governor right. The bit about not being able to stop a diesel at full throttle really resonated; though mine DID eventually stop. Hope you get it sorted.

[DougR]

Originally Posted by Mbass

Thank you for the thread Info I am hoping the 2002 fuel system is similar my engine was also not used for an extended time and the throttle and governor do not seem to be working. Nor the shut off any help would be greatly appreciated. The throttle has no effect on engine speed. Mike

Hello Mike,
Conceptually, the 2030 engine fuel system as discussed in this thread, and your 2002 engine fuel system are similar, but at the same time different in construction. Both have governors, both have a linkage to the injection pump(s), and both have piston type injection pumps to create high pressure fuel to feed the injectors.

THE storage problem that frequently occurs in these high pressure injection pumps is that old fuel in the injection pump becomes sticky or turns like varnish,
and gums up the plungers in the injection pump. Usually the injection pump camshaft has the power to push the plunger up on its pump stroke, but the internal springs are not strong enough to push the plunger back down to follow the cam, and the engine will not run. Not only does the plunger go up and down, but it also has to rotate on its vertical axis, and this rotation is what controls the fuel quantity delivery. Sometimes the piston is free to move up/down, so the engine runs, buts it’s linkage is gummy and can’t be turned by the governor linkage so there is no throttle control.

In your case, the 2002 engine has two high pressure injection pumps mounted on the port side of the engine, and they are linked to the governor by a flat control rod that slides fore and aft in the block adjacent to the pumps. When you call for more or less fuel with the throttle lever, you create spring pressure that slides the control rod one way or the other. The control rod has a small notch cut into it right by each injection pump and there’s is a small lever on the pump that fits into that notch. Movement of the control rod moves the small lever which rotates the internal plunger in the pump and increases or lowers the amount of fuel injected, therefore controlling RPM.

You mentioned that you rebuilt the engine.....did you have the injection pumps out of the engine block? The most common cause of loss of RPM control is that the pump(s) are removed from the block, and then replaced and the little lever is not fitted into the notch in the control rod. This means that the lever presses down on the rod and clamps it in position. The engine runs but the RPM cannot be controlled. Or the little lever is gummy to the point that the governor springs cannot move the control rod.....

First thing I would do is remove the threaded plug on the back of the block, right behind the second injection pump and look in that hole with a mirror. You will see the end of the control rod, and it should move fore and aft with throttle and stop lever motion, or with your fingers. If the control rod moves freely, then you probably have a linkage issue in the governor, and that’s where you should look next. If the rod won’t move then the next thing I would do is lift out both injection pumps from the block.

This is straight forward, but you need to mark the pumps so you know which goes where, and you need to be careful with the gaskets/ shims which are located under the pump flange, as these control the injection timing for each individual pump. When the pumps are out, check to see if the control rod is now free to move back and forth. If yes, start looking at the pumps to see why they won’t move. If the little control levers are bent up you know what the problem was....they didn’t get into the notch in the rod. If the levers won’t move back and forth freely then maybe it’s time for an injection shop to take a look at the pumps, to disassemble and clean...

If the control rod is still not moving it’s time to dive into the linkage behind the control lever cover. Here’s its best to have a shop manual and also a parts book to see how things are supposed to be arranged. You can also have a look in thru the oil fill cap and see if the governor weights and sliding sleeve are free move.
I really doubt you will find anything wrong in here, but maybe a spring has broken or something obvious like that.

Hope this helps and gets you on your way.

[August M]

I have had this same problem with a Perkins Perama M30, which is the same base engine as the Volvo MD2030. The engine is 30 years old but never been run since new, when it was started the throttle would not control the revs, but it could be feathered with the stop lever and also stopped with the stop. By itself the revs would take off and runaway.
We found that the tab on the internal mechanism was the same that sandman noted, bent from perpendicular by approx 20 deg. When this was bent back to perpendicular and reassembled the engine was perfectly fine, runs and is controlled normally.

During the process of getting the engine commissioned I did get the injector pump reconditioned to remove any old diesel that had glazed on from when it was set up at the factory.

[HelgeS]

Same problem on my md2040. On the injector pump the stop lever is hinged to a hammer. It was stuck. After loosening it, everything was normal.
https://youtu.be/fIYBAWInnZQ