Bleeding problem md2020

[Bav32]

Hello everyone,

I have an issue with my fuel-system. I changed the pre-filter and the engine fuel filter.
When trying to bleed the system, I dont get any fuel even to the pre-filter. I have been pumping my thumb sore with the engine manual pump. The only thing I hav'nt checked is the cutoff valve. I have never turned it over before this and this is my first time to change the pre-filter on the boat.

There was a really small amount of brown-ish stuff in the bottom of the pre-filters water separator. I don't think that this would clogg the fuel-lines.

Am I really on the wrong track when i suspect the cutoff valve? Can the valve really break when you turn it?

[Ronald]

Could be very well your cut of Valve.

 Had the same last year and found  the valve clocked with dirt, cleaned it out and problem solved

Good luck Ronald.

[Salty]

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Am I really on the wrong track when i suspect the cutoff valve? Can the valve really break when you turn it?

If yours is the same shut off valve as that supplied on many of the boats from the early 2000s, then it’s unlikely that it will actually shut off completely. Some of us have run our engines for hours and hours with the so called shut off valve in the shut position. As for breaking, I doubt that would happen. On my boat the only difference it made having the valve in the shut position was to restrict the engine rpm to something around 2000.

I too have an MD2020 engine, and like you I find the priming pump to be a bit hit and miss as to whether it works when I want it to. I gather it will work better when the engine crankshaft is in a certain position, but I can’t remember what that position should be. This is mainly because I do things perhaps a bit differently, and don’t use that hand pump at all.

Instead of fiddling around with the hand operated priming pump, I make a point of changing only one filter at a time, and when the first one is done I don’t bother with that tiresome hand pump, instead I go up and start the engine in the normal way and run it at slow speed. Usually enough fuel remains within the injector system for the engine to start and run, and at which point the capacity of the fuel pump far exceeds the amount of fuel the engine needs to run at slow speed. This sucks the fuel in from the tank and fills up the bowl around the filter I’ve just changed. Apart from a minor reduction in rpm as it gets past the last bit of air in the system before the speed comes back up, I’ve not needed to use the hand pump at all since the very first filter change I did. Once the first filter has been done and the engine run, then do the second filter in the same way. It has worked for me every time for the last eight years with one change of each of the filters every year.

[dawntreader]

Hello everyone,

I have an issue with my fuel-system. I changed the pre-filter and the engine fuel filter.
When trying to bleed the system, I dont get any fuel even to the pre-filter. I have been pumping my thumb sore with the engine manual pump. The only thing I hav'nt checked is the cutoff valve. I have never turned it over before this and this is my first time to change the pre-filter on the boat.

There was a really small amount of brown-ish stuff in the bottom of the pre-filters water separator. I don't think that this would clogg the fuel-lines.

Am I really on the wrong track when i suspect the cutoff valve? Can the valve really break when you turn it?

You may just have an airlock  to the manual pump. Try opening the bleed screw a little, depress the pump and keep holding it down, tighten the bleed screw and release the pump again. Do this a few times and you may get results  Also, have you just tried running the engine - sometimes they self-bleed 

[Bav32]

Thanks for the quick replys!

I'm sure I will remember to change just one filter at the time next year . I have tried pouring fresh diesel straight into the engines fuel filter and started the engine. The engine ran fine a couple of minutes before stalling. Result was that I did'nt get any fuel even to the pre-filter.

I'll try to check the cut-off valve tomorrow. I was thinking of pressing some air into the fueltank via the pre-filter couplings, just to see if there is a blockage. Any thoughts on that?

[Yngmar]

My engine usually starts fine without bleeding after messing with the fuel supply (filter changes, etc.), but the one time it didn't, I had an air leak at the filter, so it couldn't suck fuel - it sucked air instead. Something worth checking for.

[Bav32]

My engine usually starts fine without bleeding after messing with the fuel supply (filter changes, etc.), but the one time it didn't, I had an air leak at the filter, so it couldn't suck fuel - it sucked air instead. Something worth checking for.

This was my first thought. But can I have messed up the pre-filter gaskets so badly that it sucks air instead of fuel from the tank? 

I could not find any good pictures or instructions online how to install the filter. I thin the partnumber for the waterseparator/pre-filter is 833971

https://www.volvopentashop.com/epc/en-US/Details/PentaPartsCatalog/7746800_040?path=MarineDieselEngines/7746800/7746800_23/7746800_040

[PEA-JAY]

Changing the pre-filter can be awkward if you try and do it still fixed to the bulkhead. I always first drain it then undo the two retaining bolts and nuts so I can invert it and change all the seals comfortably. Buy a Delphi HDF296 filter and you’ll find all the 5 seals and instructions.  About the valve, I suggest you remove and clean it as you might find gung blocking it. My valve is original and works perfectly! I suggest fitting an in-line transparent diesel filter at the exit from the tank so you will spot any debris or dirt immediately!

[Ricd]

When I had the md2020 I never once managed to prime it using the lift pump. I always used the engine starter to drive the fuel through with my engineer mate cracking the bleed right open and on one occasion cracking the last injector fuel line open, and me at the helm pushing starter button in roughly 8 to 10 sec bursts. We only did this as in marina we had option to go onto shore power if starter motor hammered battery too much, which it actually never did. As long as I had that engine I was praying I never had to do it at sea.  I wad thinking of changing the pre filter to the one Asap supplies with an palm push priming pump on top. In end changed engine to a D1-30 which has exactly that primer

[Bav32]

When I had the md2020 I never once managed to prime it using the lift pump. I always used the engine starter to drive the fuel through with my engineer mate cracking the bleed right open and on one occasion cracking the last injector fuel line open, and me at the helm pushing starter button in roughly 8 to 10 sec bursts. We only did this as in marina we had option to go onto shore power if starter motor hammered battery too much, which it actually never did. As long as I had that engine I was praying I never had to do it at sea.  I wad thinking of changing the pre filter to the one Asap supplies with an palm push priming pump on top. In end changed engine to a D1-30 which has exactly that primer

Oh snap... maby I have to buy a can of diesel and try to fill the filters and start the engine. Before that I will have a look at the cutoff valve.

Does anyone know if the valve is also a one way checkvalve?

[dawntreader]

No, not a 'checkvalve' just a simple open/closed device

[Ricd]

When I had the md2020 I never once managed to prime it using the lift pump. I always used the engine starter to drive the fuel through with my engineer mate cracking the bleed right open and on one occasion cracking the last injector fuel line open, and me at the helm pushing starter button in roughly 8 to 10 sec bursts. We only did this as in marina we had option to go onto shore power if starter motor hammered battery too much, which it actually never did. As long as I had that engine I was praying I never had to do it at sea.  I wad thinking of changing the pre filter to the one Asap supplies with an palm push priming pump on top. In end changed engine to a D1-30 which has exactly that primer

Oh snap... maby I have to buy a can of diesel and try to fill the filters and start the engine. Before that I will have a look at the cutoff valve.

Does anyone know if the valve is also a one way checkvalve?

You don't need the can of diesel. the starting motor will fill the filters and start the engine as soon as the system is fully primed. 

Interestingly the question of the fuel valve keeps being mentioned.  When you changed the course filter was there any sign of gunge on it?  If it was clean and thus your fuel is clean, why suspect the valve?  I think you just have a fuel system that is a pig to prime.

[Bav32]

Ricd, you might be right about the fuelsystem being a pig. 
There was a small amount of brown gunge in the bottom of the waterseparator.

I allready tried to start the motor. But I can't get any fuel even to the waterseparator. That is why I suspect the valve. I'll be going to the boat tomorrow and try once more.

[Ricd]

Gunk in the separator sounds suspiciously like bug so valve may be blocked. But, I assume engine ran perfectly just before you decided to change filter so why should changing filter cause valve blockage. If it is bug need to consider what is in fuel tank...have you been using  any sort of fuel treatment?

If bleeding using engine you need to open bleed screw, even remove it, for starter motor to prime system. It requires two people as as soon as fuel flows at bleed screw it needs to be closed while second person is at starter button.

[Salty]

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If bleeding using engine you need to open bleed screw, even remove it, for starter motor to prime system. It requires two people as as soon as fuel flows at bleed screw it needs to be closed while second person is at starter button.

The method I have used as noted in my earlier posting above has never required a second person, neither have I needed to open any bleed screws. As I said then, having changed the first filter I then went up and started the engine in the normal way, but ran it at slow speed, in other words at tick over speed. I left it to run for five or ten minutes while I had a coffee, then stopped the engine and changed the second filter and ran the engine again as before. I didn’t open any bleed screws or loosen any pipe work at any time in order to bleed off anything.

The only part that is a bit of a pig to do is the primary filter because it’s just a bit awkward to get at. In order not to spill a lot of diesel fuel into the bilge, I’ve taken an old empty plastic milk bottle of the 2.272 litre (4 pint) size and I’ve cut it to remove the top and part of the side while retaining the handle and the bottom rectangular part of the container. This with a little bit of persuasion fits nicely under the original CAV primary filter such that as the filter is undone it’s contents drop into the bottom of the milk bottle and not into the bilge. Rebuilding that filter is something you need to take a bit of care about as there are too many opportunities to get it wrong with the result that it could subsequently leak air or diesel fuel resulting in poor starting or dirty bilges. The secret being to take lots of photos on your mobile as you go so that you have a complete record of where each rubber joint fitted.

[Ricd]

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If bleeding using engine you need to open bleed screw, even remove it, for starter motor to prime system. It requires two people as as soon as fuel flows at bleed screw it needs to be closed while second person is at starter button.

The method I have used as noted in my earlier posting above has never required a second person, neither have I needed to open any bleed screws. As I said then, having changed the first filter I then went up and started the engine in the normal way, but ran it at slow speed, in other words at tick over speed. I left it to run for five or ten minutes while I had a coffee, then stopped the engine and changed the second filter and ran the engine again as before. I didn’t open any bleed screws or loosen any pipe work at any time in order to bleed off anything.

The only part that is a bit of a pig to do is the primary filter because it’s just a bit awkward to get at. In order not to spill a lot of diesel fuel into the bilge, I’ve taken an old empty plastic milk bottle of the 2.272 litre (4 pint) size and I’ve cut it to remove the top and part of the side while retaining the handle and the bottom rectangular part of the container. This with a little bit of persuasion fits nicely under the original CAV primary filter such that as the filter is undone it’s contents drop into the bottom of the milk bottle and not into the bilge. Rebuilding that filter is something you need to take a bit of care about as there are too many opportunities to get it wrong with the result that it could subsequently leak air or diesel fuel resulting in poor starting or dirty bilges. The secret being to take lots of photos on your mobile as you go so that you have a complete record of where each rubber joint fitted.

Fair point Salty, I have to admit I had not fully read your previous post.  The reason I like two people as I generally change both filters at same time and really do need to bleed system with starter motor before engine will fire up.  I like to be at engine button to ensure I only run the starting motor in less than 10 sec bursts so need someone down below to close bleed screw as soon as fuel is flowing.  I will certainly give your method a try when I next change the filters, one at a time.

[Bav32]

Problem solved. Thanks for all the great advices I'm sure I'm much more familiar with the engine and fuel system now.

I tried the starter motor trick, but I probably did'nt do it long enough. Then I took a small rubberhose and sucked the fuel to the pre-filter. After that I sucked the fuel to the engines fuel filter via the primingscrew. I noticed that my manual pump does not work. No fuel came out when pumping by hand. That is something I have to have a look at.

Now the engine has been going for 15 minutes. All the air is probably out by now.

Thanks again to you all!

[Rampage]

I’ve got an outboard fuel primer bulb in between the primary and engine filters.  I change both filters and then use the bulb to pull fuel through the primary and then into the engine filter.  Takes a few pumps to fill each filter, then close the bleed valve on the engine filter.  The only time I’ve ever encountered a problem was when I’d made a nonsense of reassembling the primary filter and couldn’t get it to prime...  I’d got one of the several seals wrong.

[Bav32]

I’ve got an outboard fuel primer bulb in between the primary and engine filters.  I change both filters and then use the bulb to pull fuel through the primary and then into the engine filter.

How stupid I feel now. Why didn't I think of that? 

[dawntreader]

I’ve got an outboard fuel primer bulb in between the primary and engine filters.  I change both filters and then use the bulb to pull fuel through the primary and then into the engine filter.  Takes a few pumps to fill each filter, then close the bleed valve on the engine filter.  The only time I’ve ever encountered a problem was when I’d made a nonsense of reassembling the primary filter and couldn’t get it to prime...  I’d got one of the several seals wrong.

Very good idea - thanks for sharing