Diesel Won't Start After Filter Change

[shamrock]

I have a Universal 24 hp diesel with a Racor and then an engine mounted fuel filter, electric fuel pump. I noticed some difficult starting about a week ago and just changed the engine mounted filter. It was full of dirty water. I screwed on the new one, bled at the filter, then at the injectors with plety of diesel pouring out of both of the bleed screws. I tried to start and wound up cranking and cranking.

I read a couple of other threads here and some advise to fill the filter before installing? could that be it, even if fuel is getting to the injectors?

any thoughts are greatly appreciated!

[DeepFrz]

You might try cracking the fuel injector lines at the injectors to make sure you have all the water out of the lines.

As a point of interest how did water get to your secondary filter. The racor should have stopped that.

[Lotustrbo]

I always had to fill the filter(s) with diesel prior to starting to keep all (well most) the air out once started the engines would take care of any remaining air in the system.

[skipmac]

If you had water past the Racor and into the secondary that is not good. Unless it was totally trashed or had some kind of problem the Racor should have stopped all the water. Did you also drain and change the Racor?

If you are lucky and your filters are lower than the fuel tank then they will fill by just opening the line or bleed on top of the filters. If not then prefilling the filters is a good idea.

Are you sure you're getting clean diesel to the injectors and not still water from the lines?

[shorebird]

I'm with skipmac. changing only the secondary filter could be a waste of time if you havn't also changed and bled the primary racor.

[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!

[noelex 77]

Don't forget to shut off the seacock ( until it starts) with that much cranking.

[skipmac]

I am not totally clear on whether or not you have purged the lines all the way to the injectors on the block. With as much water as you found in your system I would be very concerned that you have water and crude in the lines past the injector pump to the injectors themselves. Also, be aware that getting water and crude in the injector pump could cause damage, expensive damage.

If you haven't already done this, loosen all the fuel lines feeding directly to the injectors and turn over the engine. If you can, try to catch some of the output in a small cup or just absorb it onto a clean, white rag to try do determine if you have clean fuel or if you see any crud. If you did get water all the way to the injectors it is possible that the injectors are plugged up at least partially and you may not be getting fuel or perhaps not getting a proper spray pattern into the head to fire the engine.

[David M]

It sounds like you have done everything. Time to call in a diesel mechanic. You may have introduced water or solids into the injector pump.

A large primary filter with a water alarm is always a good idea for a marine Diesel. A dual filter is better so you don't have to introduce air into your fuel system. Electronic fuel pumps are helpful so you don't have to hand pump the primary fuel pump. Those are so inexpensive and practical I don't know why all diesels don't come with one. They have been on cars forever.

[bruce smith]

Originally Posted by noelex 77

Don't forget to shut off the seacock ( until it starts) with that much cranking.

or even better, pull the impeller off. You may be filling your muffler with seawater, which will soon back fill into the exhaust valves.
Was the engine running well before this filter change?
You gotta get a handle on all this water in the fuel!!

[David M]

Condensation forming in fuel tanks is a good reason to leave fuel tanks topped up as much as is practical. A water alarm in your primary fuel filter will catch that problem before the water has a chance to do damage. I make it a point to inspect the bottom of my fuel bowls for water occasionally. The good ones have a petcock on the bottom for draining any water that accumulates. Use your secondary essentially as a backup in case somehow your primary fuel filter fails to do its job. I match the micron size of my primary to my secondary, so I don't have to change out the secondary nearly as often as I change out my primary filter. With a dual system the primary is very easy to change out and does not introduce any air into the system. Others people like to uses a coarser filter for their primary and a finer for their secondary. That's fine and it works but I prefer not to do that because of it being such a pain to change out the secondary...EVERY single time you do a filter change.

[Blue Stocking]

I would suggest that he do a serious check back to the tank and pickup.
For water to get to the secondary filter would mean that the primary was full of water up to the flow level.
How long had this situation taken to accumulate?--or am I missing something?

[GordMay]

Universal Diesel Operation & Maintenance Manual
Page 28
➥ http://www.ewmanchester.com/CalDocs/...s%20Manual.pdf

Service Manual ➥ http://www.ewmanchester.com/CalDocs/...24_Service.pdf

[sailinman]

how does a water alarm work in a fuel filter?

do you have a link to one?

thanks

[svHyLyte]

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.

Good luck...