Originally Posted by shamrock
This morning I replaced the racor filter. the bowl had water and sludge in it.
I bled the system again, had a ton of air come through as the Racor filled with diesel. the fuel I saw coming out of the bleed screws looked perfectly clean and it seemed like there was plenty of pressure in the system as diesel was squirting out.
I tried to start again with no luck. Then took the fuel line off an injector and took a look as suggested by DeepFrz. The electric fuel pump was operating. there was a bead of some liquid either water or diesel or both. Should the fuel lines past the injector pump be pressurized like they are at the bleed screws? If so, perhaps thats my issue? What next??
Many thanks for the input!
I am not a diesel mechanic
nor are engines my specialty. I did, however, just go through a rather time consuming repair of the fuel system on our 4-108 and learned a lot--and I did sleep in a Holiday Inn Express the other night!
N'any case, if you had "dirty water" in your secondary fuel filter, your electric pump
pushed it through the Racor, into the secondary and likely into the lines to the injection pump. Replacing the secondary served no useful purpose as water may have already made its way past that. Going back and clearing/replacing the Racor, without also again bleading line from the Racor to to secondary and then replacing the secondary again, will have served no useful purpose.
The Racor has a check-valve that prevents fuel in the line between it and the engine/secondary fuel filter from draining down when the Racor's unsealed--usually a nice feature that minimizes having to blead the fuel system when the Racor is cleaned out. With contaminated fuel already past the Racor, however, the check-valve will have held that contaminated fuel in place and than allowed it to be pushed into the secondary when you repeated the effort to start the engine. It would be wise to again replace the secondary and then crack the bleed screws on both the secondary and on the injection pump and run your electric pump
until clean, uncontaminated fuel issues from both. Then close the bleed screw on the secondary (first) and, finally, the bleed screw on the injection pump. Once you've done that, you can crank the engine and loosen the fuel lines from the injection pump to each of the injectors, in turn. Once you've got clean, uncontaminated fuel at one of the cyclinders, the engine will likely start but run very poorly as you crack the fuel lines to the each injector in turn. (Be very cautious around the injector lines as high pressure fuel can do some serious damage.)
As others have advised, it would be wise to close your raw water
intake to prevent filling the muffler--and potentially a cyclinder--with sea water and, potentially, removing the raw water
impellor, or at least opening the pump and thoroughly lubricating the pump walls and faces with non-petroleum based grease to prevent the impellor from self distructing while you're trying to get the engine to start. As long as the impellor's well lubed, the engine can run a few minutes without the raw water valve being opened without ill effect.
In future, when cleaning
the fuel system, work from the fuel tank
to the injectors. Your Racor should be check periodically for any sign of water/debris and drained/cleaned out as necessary. Frankly we check outs weekly and more often when we're motoring a lot, just to be on the safe side.