Clogged Diesel fuel filter on W3eserbeke 10-2

anchorclanker · Mar 18, 2013

If you have water in the filters and the engine quit, and wont start, you have water in the engine fuel system. Before you leave the engine sit two weeks, you should do as much as your able to clear the water out, reprime the engine and get it running. Water in the pump and injectors, not to mention what may have been sprayed into the cylinders, will do your engine no good at all.

Likely there is water in the tank/tanks, and it could be a lot. Rather than screw with them now, for the time being you can attempt to run the engine off a small tank, can, or bottle of diesel. Dump out the water in the filters and put in new ones, or reuse the old ones if your reasonably sure their clean. Run some fuel line from the filter into your bottle or whatever, and temporarily keep the return line going to the tank or dump it into the bilge. Running the electric pump or hand priming pump, some return fuel should come out the return line. Keep it running until its solid fuel clear of water. Keep adding fuel to your supply as needed. Once the fuel is clear with no water present, stop pumping. Crack the injector lines loose at the injectors, and again, with your supply filled, start the pump and crank the engine. Crank until you see fuel more or less free of water. A little wont matter, were just trying to get it running, the water will clear itself. But you need to see mostly fuel at the injectors. Stop cranking the engine, again make sure your supply is filled, tighten the injectors and attempt to start it. If the fuel return line is pumping solid fuel, put it into your supply bottle/tank. Run it as long as your able, but let it run at least 10 minutes so as to clear any residual water from the pump and injectors, and blow out whatever may have been pumped into the engine. Change the oil next time your at the boat.

If you cant get it running, before abandoning it I would advise removing the injectors, cranking the motor to blow out any water, and putting some kind of oil into the cylinders, and cranking again to blow out the excess oil and lube the cylinders.

anchorclanker · Mar 18, 2013

Diesels most often have engine driven mechanical fuel pumps, called lift pumps, to feed fuel to the injection pump. Others have an electric lift pump that runs whenever the power is switched on to start the engine. On engines with mechanical pumps there is often a manual operated hand pump incorporated.

The injectors are either screwed into the head, or clamped down with a plate and stud bolts. The later is the way most Yanmars are and they can be hard to remove if they havnt been out in a while. The filters trap debris, and can to a point separate water, but they will pass water once they get flooded.

If you can drain the filters of water and get fuel through to the injectors it should start. Again, loosening the lines a bit at the injectors will allow water, air and fuel to pass without being injected. Yes, the pump will flow fuel continuously. If you have an electric lift pump, it will be running constantly with the power on.

I hate the stuff and normally refuse to use it, but if I was going to be away from it for two weeks I would rather it ran first. I would do all the bleeding I could of water and if unable to get it to fire, I would try a lil bit of starting fluid. If you only spray it in while the engine is turning it will have the least negative impacts. Start with very small shots and slowly increase the amount until it fires.

You also need to close the sea cocks to the engine so it wont draw water back in though the exhaust. Keep it closed until the engine starts.

Roger Long · Mar 19, 2013

anchorclanker said:
I would try a lil bit of starting fluid.

Be very careful. Starting fluid can fire off before the piston reaches top dead center and kick the engine backwards. Things can get damaged in the starter or worse if another cylinder is firing normally at the same time.

WD-40 is less likely to pre-ignite and will work as a starting fluid for diesels. It also has the advantage that, if the engine doesn't start, you will at least have gotten something in it that will help protect the cylinders from the effects of any moisture that is in them.

cbourne200 said:
Any other suggestions vs clogged filters?

There are probably hours of reading on this forum if you do some searching?

Executive summary:

If your tank has inspection ports, the best thing you can do is empty it and physically scrub and clean it until it is as clean as new.

If you can't reach the insides, you'll have to spend a couple hundred bucks for a fuel polishing service to come and clean it. There are two kinds of these services. One just runs the fuel around and around through large filters, usually by tapping into the existing plumbing. These are just polishing your wallet. The service you want will use a suction wand that they can stick around into the tank corners and return the fuel with a pressure wand, sort of like a powerwasher, to blast crud off the tank sides.

Change your filters every year whether they need it or not. The elements get weakened and can leak.

I'm a big fan of onboard, full time, polishings systems. They need not be expensive. Mine keeps my system surgically clean:

http://www.cruisingonstrider.us/FOpolishing.htm

anchorclanker · Mar 19, 2013

Roger Long said:
Be very careful. Starting fluid can fire off before the piston reaches top dead center and kick the engine backwards.

I am not a proponent of starting fluid, not at all. But as I said, if it was the choice between that or letting it sit two weeks with water in it, I would take the chance as a last resort. Also, as I said, small amounts only after its turning over. I havnt owned a can wd-40 since I worked around aircraft and heard (and saw) what it does.

Further, before using it as a last resort, I would have done everything possible to either get it running, or protect it, such as removing the injectors, clearing the cylinders and lubing them.

But at least it ran, and 10 minutes, while not a great amount of time, is enough you should be okay until you can get back to it.

BarryL · Mar 21, 2013

Hey,

Good job and it sounds like you are a competent mechanic and are learning a great deal.

One thing you need to know is that when the electric fuel pump is running it is pumping fuel from the fuel tank through the fuel lines and then back into the fuel tank. The fuel is NOT going through the fuel injectors, those flow fuel when the engine is being cranked over. So, if you have air or water in the fuel injector lines you need to either open the bleed valve (if there is one) or remove the injector lines and run fuel through them.

Now once you get the fuel in the tank cleaned, you can put the system back together, bleed the air out of the lines and the engine should start and run.

Lastly, I have a Racor fuel filter / water separator on my boat and it works very well. I would recommend you get one so this problem doesn't happen again. Oh yeah, make sure you check the o-ring on the fuel fill cap because if the ring deteriorates it can less rain and salt water get into the fuel tank.

Barry

tedsbeds · Mar 22, 2013

I have the same boat and had basically the same problem but a different cause. Had injectors rebuilt after PO let the boat sit for 2 years. Replace all filters including one in lazerette. Still would not start. Fuel pump ran continously at high speed which is symptomatic of not achieving fuel line pressure. After much research found that cover on bronze filter/seperator in lazerette was not tightened sufficiently. Air was being sucked into the line at that point. Retightened that cover and pump went from high speed cliicking to slow rythemic click. Engine started after that. FYI there is a fuel shut off on the top of the tank at pick up line. The only wat to reach it is to lie on your back in quarter berth and reach up to the top of the tank or remove the instrument panel. I did that, removed the valve at that location and installed one just before the first filter in the lazerette.