Volvo Penta MD2030B governor problem

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

have you found the problem w/gov yet ,cuz ive got an md 2020 that i am rebuilding that when i opened up the front cover the thin metal flap was bent at a 45*angle that looks like should have been 90*that deals with the stop control ,it doesnt show in any books i can find how its supposed to be ,but i assume that if i continue w/rebuild i will have similar probs

Well, I actually ended up replacing the entire engine with a Yanmar, but that was due to water ingress in the cylinders and seized pistons. Without cylinder liners, fixing that particular problem would have been a nightmare. The engine was a bit on the small side for my boat anyway, so...

On to your problem. Before seizing up, I did figure out what was wrong with the centrifugal regulator for the fuel injection pump. As you mention above, there was a thin metal flap which had been bent to about 45 degrees, by operating the manual stop lever while the fuel pump control rod was stuck. The effect of this was that the centrifugal regulator couldn't provide enough travel on the fuel pump control rod to prevent a runaway engine, and secondly, the manual stop lever couldn't push the fuel pump control rod to 0%.

Hope this drawing makes this a bit clearer:

And a picture of the damaged regulator arm on my Volvo Penta:

Thank you very much I don't know where you got the drawing but have been looking for that all over the web. that's exactly what my problem is I couldn't explain it to any of the experts over the phone no one seemed to get it I guess it takes someone with experience on that exact problem to help I really do appreciate it I can put my engine back together with confidence now

No problem at all. I recognize the problem with the "experts" on the phone. When I told them it was a tiny MD2030 from the 90's, they suddenly couldn't help me anymore.

If you need the complete schematics for the engine, I can highly recommend https://www.marineparts express.com/chooseschematics.html (Remove space in the middle of the link address, the naughty word is censored by the forum)

Here you can find complete schematics for pretty much any marine engine you can think of. The MD2020 can specifically be found under Volvo Penta Marine Schematics, then Diesel, then MD2010B_MD2020B_MD2030B_MD2040B_MS2L-D_MS2A-D_120S-D_MS2B-R_MS2A-E_MS2L-E.

Hello,

Been a couple of years since this post but want to say thank you! This is exactly the issue I had with an VP MD2010.

Some background, boat had been sat idle for 11 years we think, changed all filters, oils, fuel, fuel tank was gross. But a bit of easy start and away she went……but wouldn’t stop. 4000rpm came up and managed to stifle her by blocking the air intake.

Spoke to a lot of engineers, 8 in fact. They all said the governor would be stuck open, a good friend of mine who was with me suspected the fuel injection pump. Straight forward enough to get the fuel injection pump out, first specialist told us was knackered and needed a new one. Wife wouldn’t let me buy a new one! Thank god! Took it for a second opinion. What a legend, cleaned it up and told me to bugger off! Said there was some varnishing and the fuel delivery valve was stuck open, but nothing wrong with it.

That’s when I found this forum. My intermediate lever had a near 45degree bend on it rather than 90. Straightened it and rebuilt. Hardest part is the water pump!

Started her up, ran and purred like a kitten. Didn’t run away at all, sat at idle, brought the revs up to 2000rpm, then she dropped right back. Perfect!

What caused it to bend is what is frustrating me. I had an “engineer” jump on whilst we were trying to start it, he was ramming the stop in and out. I questioned at the time why, shuts off fuel not decompress so couldn’t see his logic. So I think the fuel pump was stuck, then ramming the stop bent it. But unfortunately we’ll never really know. But the bend lever arm was absolutely the cause to it running away. I hope this helps anyone else who has the same problem.

Many thanks again!