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

 

[Scott Danforth]

find a diesel mechanic and a fuel pump rebuild service

the fuel pump rebuild service will test your fuel pump and governor on their bench
the diesel mechanic will install, time and verify your running properly.

your fuel shut-off isnt working
your governor has a few issues.

 

[SandMan874]

First off, thanks for the quick answer.

As I write in my original post, the fuel injection pump has been overhauled and tested by a local company specializing in this. However, I am beginning to wonder if everything was done correctly, hence the questions here on the forum.

I am also a bit confused as to how they are going to test the governor on their bench. The centrifugal governor mechanism on a VP MD2030B consists of weights mounted on the end of the camshaft working together with some arms and springs mounted inside the timing gear housing. Unless I deliver the complete engine to a workshop, I don't understand how a diesel mechanic can test the governor.

I hoping somebody has had some experience with similar problems with an MD2030 or a not too dissimilar engine.

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?

See the attached picture.

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

 

[Sbirdscotty]

sandman, did you ever solve your problem? I am having a similar problem on my totally rebuilt MD2030C engine. I am reluctant to take off the front housing and take the governor to a local shop.