MD11C stop control not stopping engine

[vpguy]

Hi there,

My boat is on land with no seawater intake and I installed a new Racor primary fuel filter yesterday for my Volvo Penta MD11C.

I was having trouble using the fuel hand primer to prime the system, so decided to crank the engine a little to help it by moving the camshaft into a different position. Suddenly the engine started, but I couldn't stop it by pulling the fuel stop control. I pulled the top of the Racor off to introduce air. That didn't work and I didn't see any fuel inside the Racor filter at least from the top. What was the engine's fuel source and why didn't the stop control work? Could it be oil leaked into the cylinders? Old diesel from the previous season somehow inside the engine?

Later the engine died on it's own after about 2-3 minutes, roughly around the same time I pulled the cap on the freshwater cooling, which I suppose is a coincidence and I also found what seemed to be alot of clean diesel in the Racor water separator.

I'm currently consulting my diesel engine book for clues. Thanks in advance for any advice.

 

[Graham376]

No idea why the stop cable didn't work unless something was restricting full travel. Would have been simpler to just decompress both cylinders to stop the engine.

 

[croc9968]

I would be interested in hearing the responses to your latest post as I have a 1984 MD11 and I'm about to service for the first time (me, not the engine). I have a CAV Delphi water separator in my system so will be interesting to have your insight into our engines. Any tips you want to share? Where have you gone for your filters and parts?

 

[Bilgediver]

Later the engine died on it's own after about 2-3 minutes, roughly around the same time I pulled the cap on the freshwater cooling, which I suppose is a coincidence and I also found what seemed to be alot of clean diesel in the Racor water separator.

I'm currently consulting my diesel engine book for clues. Thanks in advance for any advice.

You mention removing the cover of the Racor. If this is the filter you just fitted and it is between the fuel tank and lift pump where most people fit and this is the filter that you lifted the cover to stop, then the engine would normally run about 5 minutes before stopping as it is using up the fuel in the engine filter and fuel lines. ?

I would expect to see fuel in the water separator in the fuel line and would be concerned if I saw an amount of water. Under ideal conditions it is rare to see anything other than a very small amount of water at the bottom of the glass bowl with the diesel floating above it.

Your engine may be fitted with a remote pull for setting the cold start. Do you have this and is this what you pulled?

The engine stop is connected to the governor speed lever and has to be adjusted correctly. In order for it to operate as intended there should be a spring cushion mounted on the linkage between the speedl lever and the Teleflex. with the throttle in the neutral position operation of the Stop pull pulls the fuel lever past the idle position compressing this cushion so stopping the engine. Sometimes over time this spring cushion is either lost or incorrectly assembled which means you are trying to stop the engine against the tension of the Teleflex. Also if the cockpit lever is not in the idle position then operating the stop control, you will be trying to pull the Teleflex to the stop position which could be impossible if it is stiff. Check your throttle and stop system. It is possible to set the governor linkage to operate without the spring cushion but it needs to be done very carefully.

 

[vpguy]

You mention removing the cover of the Racor. If this is the filter you just fitted and it is between the fuel tank and lift pump where most people fit and this is the filter that you lifted the cover to stop, then the engine would normally run about 5 minutes before stopping as it is using up the fuel in the engine filter and fuel lines. ?

I believe that the system was not primed during this time, but having thought about it, it is possible that repeated crank attempts drew in fuel into the lines? This would make sense even as I didn't see anything in the water separator at the time until the whole incident was over.

I would expect to see fuel in the water separator in the fuel line and would be concerned if I saw an amount of water. Under ideal conditions it is rare to see anything other than a very small amount of water at the bottom of the glass bowl with the diesel floating above it.

If the diesel here is totally clean, does that mean you can essentially reuse it as in 'fuel polishing'? I have kept it for later as a top up for the filter amongst other things.

Your engine may be fitted with a remote pull for setting the cold start. Do you have this and is this what you pulled?

I have a stop control which I have always used and has worked flawlessly. I initially believed it to be cutting the main fuel line, but read that it is actually stopping the fuel at the injector pump? When me and another guy looked at it, I could see it pulling something at the back of the engine, but it looked slightly cracked where the copper encases the metal wiring. I will have to investigate that.

The engine stop is connected to the governor speed lever and has to be adjusted correctly. In order for it to operate as intended there should be a spring cushion mounted on the linkage between the speedl lever and the Teleflex. with the throttle in the neutral position operation of the Stop pull pulls the fuel lever past the idle position compressing this cushion so stopping the engine. Sometimes over time this spring cushion is either lost or incorrectly assembled which means you are trying to stop the engine against the tension of the Teleflex. Also if the cockpit lever is not in the idle position then operating the stop control, you will be trying to pull the Teleflex to the stop position which could be impossible if it is stiff. Check your throttle and stop system. It is possible to set the governor linkage to operate without the spring cushion but it needs to be done very carefully.

Yes, we kept it in neutral the whole time and I will indeed check this lever. I saw a video on Youtube with an MD11C where the stop control is manually activated by hand. I may try this also next time if the stop control doesn't work in addition to using the decompression levers.

 

[Bilgediver]

I believe that the system was not primed during this time, but having thought about it, it is possible that repeated crank attempts drew in fuel into the lines? This would make sense even as I didn't see anything in the water separator at the time until the whole incident was over.

Reply

Unless you had drained the fuel system then it would have remained primed from the last time run except for where you fitted the new filter . If the new filter was fitted close to and between the lift pump and fuel tank then there would be sufficient fuel in the system to run the engine for a few minutes


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If the diesel here is totally clean, does that mean you can essentially reuse it as in 'fuel polishing'? I have kept it for later as a top up for the filter amongst other things.

Reply
The fuel in the water separator is unfiltered and yes it can be returned to the tank however it can be kept for other purposes. A mixture of diesel and engine oil makes a good release oil

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I have a stop control which I have always used and has worked flawlessly. I initially believed it to be cutting the main fuel line, but read that it is actually stopping the fuel at the injector pump? When me and another guy looked at it, I could see it pulling something at the back of the engine, but it looked slightly cracked where the copper encases the metal wiring. I will have to investigate that.


Reply

The Stop control works onto the governor speed lever and is connected to the lever where the throttle is connected. The throttle has a compression spring in its attachment and the stop cable operates on the speed lever pulling and pulling it from the idle position to the stop position by compressing the spring. The stop wire is NOT attached to the speed lever but passes through it with a collar clamped to it which allows the speed lever to move through its range .

Quote.

Yes, we kept it in neutral the whole time and I will indeed check this lever. I saw a video on Youtube with an MD11C where the stop control is manually activated by hand. I may try this also next time if the stop control doesn't work in addition to using the decompression levers.

Reply

If the lever moves by engaging with your fingers but not by using the stop control then it suggests the connections on the speed lever need tweeking. The collar on the stop wire should be fixed in a position which just allows the speed lever to slide along the wire to full throttle when the stop handle is pushed to the run position.