fuel bleeding problems

[charlesson]

I changed my Racor filter today while following the useful advice from previous posts and articles. After installing the new filter, I attempted to fill the bowl by simply using my fuel pump to do the work. The pump ticked perhaps once a second but the progress was slow. So I started the engine expecting it eventuially stop which it did since I had noT bled the system. The filter "bowl" was now about three quartes full with the fuel pump making a continuous noise with no ticking.NO fuel comes out of the bleed screw when it is loosened. I gave Up for the day. If I fill the filter all the way to the top and reinstall it is this likely to solve the problem. I also checked the bleed screws on the engine (secondary filter and injector pump) and they appear tight. The system seems not to be pressurized. I successfully bled it last year but this is the first time I changed this filter.

Thanks in advance,

Ken Heyman
1988 C34
"Wholesailor"
Chicago, Illinois

[Ray Erps "Diamond Girl" #]

Hello Ken,

If the racor filter is between the lift pump and the fuel tank, any air in the system will degrade the pumps ability to pull fuel from the tank.  Also, if the racor filter is loose, the lift pump will be pulling air through the loose fitting rather than the tank.  Also, if the fuel tank is empty, the lift pump won't have anything to pump.  I'd take a five gallon jerry can of diesel down to the boat, dump all but the last quart in the fuel tank and then dump the last quart in the racor filter and try again after checking to see that everything is tight.  With a full tank of fuel, the fuel level is pritnear high enough that a lift pump isn't even necessary.  A few thoughts anyway and I'm sure there will be better ideas coming your way soon.

Ray

[Ted Pounds]

Ken
You say the bleed screw(s) on the engine are tight?  You want to have the round bleed screw on the engine fully loose (open).  When I do that my pump has no problem filling my filter in about a minute or so.  :cool:
 By the way I don't like pre -filling my filters because of the possability of contamination when I add fuel. If I have the pump pull it all through the filter I know for sure any crud is filtered out.

Ted

[Stu Jackson]

Bleeding Diesel Fuel System

Ken

If the knurled bleed knob and/or the injector pump bolt head weren't opened, there was nowhere for the air to go!  That's why the Racor didn't fill up.  And why the pump stopped operating.

Just open the injector pump bolt, and try it again.  I usually don't fill up the Racor, just let the fuel pump do it's work.

Stu

[Ted Pounds]

Ron,

Why do you open the bleed bolt on the engine fuel filter bracket?  Even when I've changed both filters I only open the bleed valve before the injector pump and that bleeds everything just fine.

Ted

[Stu Jackson]

My Mistake

I was wrong to say: injector pump bolt head.

I meant the the bleed bolt on the top of the engine filter bracket.

Sorry for any confusion.

Stu

Here's the Universal manual reference:  http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-bleeding-fuel-system.html

[jkar]

OK, I am having a devil of a time.  Everytime I think I have the engine bled and things are working, it won't start.  I have pure fuel coming from the drain on the first filter when I open it.  I opened the nut on the second (engine) filter when I read about that and squirted pure fuel all over the engine compartment immediately.  I then undid the "knurled knob" on top, didn't get any fuel there, but I heard the fuel pump switch pitch from a "tick.tick.tick" to a much faster "tickticktick" sound.  So two questions. 1. Does any fuel usually come from that "knob" on top? I seem to remember at some point that it did, but can't say for sure.
2. If I have solid stream of fuel from the engine filter bleed nut, is there a reason to still crack the injectors?  Could air be past the filter stuck there at the injectors?

thanks, Joel

[Ray & Sandy Erps]

It's my recollection that the second knurled nut bleed screw that you speak of is tied in to the fuel return lines, so you won't see any fuel bubbling out anywhere.  There is a little manual hand pump on the top of the Racor and I think there is a little bleed screw on top of the Racor too.  It sounds like you just about have it, but I'd crack that vent on top of the Racor and give the manual pump a few pumps to make sure the Racor is bled too and then try starting it again.

I've not had to open any injector lines in the past but if your engine still won't start, I guess I would try it myself.  I would also flip over the compression release lever and spin the motor quite a few revolutions while I cracked open the injector lines to give the motor all the advantage to work out those air bubbles.  

It could have been that when the Racor wasn't bled first that all sorts of air was introduced to the rest of the fuel system.   When I've changed filters, I've always bled the Racor first and didn't have to mess with the rest of it because the motor always started up right away and self purged through that one knurled nut.

[Ron Hill]

Ken : Without filling the filter all the way full with fuel - you introduced "one hell of a lot of air" into your fuel system.  Not just a few bubbles.
You're going to have to open/close the bleed valve MANY times to get all of that air thru the system.  You may even have to open that bleed bolt on the top of the engine fuel filter bracket.  Run the engine with the bleed valve open 1/2 turn.  You'll be the first to hear, if the running engine gets a dose of air.  

It'll just take time to bleed all of that air thru the system.  Next time fill the filter with fuel and you'll be much better off.  

[sailon1]

Ken,
I have just done the same service just the other day with what sounds like the same set up. You should have started by filling the Racor first and then bleed the air out by opening the white bleeder knob on top of the Racor. The problem with the set up we have is that the fuel pump is after the Racor and this style pump is not good at pulling air out unless the pump is mounting below the current fuel level. What I recommend is to take off the filter and try again or assist the pump by using a bleeder ball installed between the Racor outlet and the fuel pump inlet. You can then turn on the fuel pump, you should hear the pump go back to tick-tick-tick after a few pumps off the bleeder ball.
Joe

[Stu Jackson]

From a search on Bleeding, scroll down to subject: Topic "secondary filter bleeding" - This is my reply to John's orignal question.  

I replumbed the pump to AFTER the Racor, and it pumps JUST FINE.  A pump is a pump, regardless of whether it's in front of or after the Racor.

Clean the pump filter at the base of the pump.


Posted: Sun Apr 03, 2005 4:52 pm    Post subject: Bleeding  
--------------------------------------------------------------------------------

John

Haven't had a leak there. New leak on old filter or new leak on new filter? Remember to lube the O ring and threads with diesel or oil before installing a new filter.

On my M25, the nut on the top of the filter housing is THE place to get the air out of the system. I do not fill the secondary (engine mounted) filter with fuel, since it is a bear to get back there and put a strap wrench on it, no less getting my hand in to get the threads started. If it is empty, I can't spill any fuel. It is difficult to avoid spilling fuel when I remove the old one.

Once the new clean secondary filter is on, I just open that bolt, run the electric fuel pump by turning on the key switch at the panel, wait till the air is gone, close the bolt, and I'm done. Even opening the knurled knob is unnecessary. I tried just the knurled knob, but that didn't work. Shucks! But the bolt on the filter housing is relatively easy to get to with a long extender on a socket or just a combination wrench. I wrote more details up on "bleeding" earlier.

The fuel pump will pump through BOTH the Racor AND the secondary filter. I re-plumbed our Racor to be ahead of the electric fuel pump on the fuel line from the tank.

I would normally just cut & paste the direct URL on the search for "bleeding" for you, but for some reason, the way this board is working recently, is that I can get the search result up on the screen, but the URL ends with "=results" and NOT the actual WYSIWYG. So if I paste that, you don't get the search results. I have to go into one specific post from the array from the search, and can get that URL, but not the full search result. Sorry. If you just try the search, on "bleeding" you'll find all of those posts.

This is one of them: http://www.c34.org/phpbb/viewtopic.php?t=1431&highlight=bleeding
_________________
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite" San Francisco Bay

[Ken Heyman]

All,

After experiencing most of the difficulties referred to in this thread, it seems that the most critical factor is having the Racor full of fuel. This was illustrated recently when I reinstalled my fuel tank after following Ron's cleaning procedure. I fully expected to have to bleed my system as air was introduced by emptying the tank and removing the fuel line to the engine. (The existing filter was new and full of few and didn't need to be removed) After re-installation, just for kicks I started the engine without bleeding the system. The fuel pump rattled for a second or two and then started ticking rhythmically. It's now five hours of running time later and all is well. The only thing I can figure is that there was sufficient fuel (pressure?) in the system to force the air out. I'm not sure where the air went but it is gone. One possibility is that my engine fuel line to the filter was a bit loose in that there was a bit of fuel around the connection. Perhaps the air was forced out there. I subsequently re-tightened it and all is well. Almost a "self bleed"!

Ken