Tech advise needed -- strange engine happenings

[wind dancer]

I turned the screw on the injector "off" (which stops the flow of fuel to the injectors) and the clicking went away only to come back again.  Must have an air leak somewhere in the system?  Either that or the model fuel pump (which is a Facet automotive (Gold?) pump) is always on when the key is on.  I didn't have time when I was at the boat to investigate further.  The Facet website doesn't give specifications for their various pumps.  I'll make a phone call when I get a chance.  From the .pdf (http://www.facet-purolator.com/mcl/media/technology/hd_pdfs/Gold-Flo_sheet.pdf
on the website, I found there is an internal filter.  I probably should take it apart and clean it too.

[Mike and Joanne Stimmler]

Jay, let me clairify that the bleed screw at the injectors does not cut off the fuel supply to the injectors, it allows you to bleed air or fuel to the return line that goed back to the tank. The engine will run with the bleed screw closed. You should be able to stop and start the fuel pump clicking by opening and closing the bleed screw with the engine off and the ignition key on. With the engine running it would be normal to hear a slow clicking from the fuel pump.
Some people leave the bleed screw open 1/2 turn and there two trains of thought on this:
1  Is that by leaving it open, it will act as a self bleeding system in case air gets in the system.
2  It that by closing it, the pump won't have to work as hard and will provide more pressure to the injectors.

I would love to get Ron's and Stu"s opinion on this and to confirm that my info is accurate.

Mike

[Ron Hill]

Mike : What the lift pump is doing is making sure that the injector pump has fuel so it can pressurize the injectors.  Our fuel tank is higher than most (boats) and down to about 1/2 tank the fuel will syphon to the injector pump.
Joe Joyce (service manager Westerbeke) likes the idea of leaving the bleed valve open about 1/2 turn and have a "self bleeding system".  Also with the bleed valve cracked open, fuel is recirculated back to the tank and subsequently re filtered thru the Racor filter.  This keeps the fuel "polished" and sucks up any junk in the bottom of the tank.
 
If the bleed valve is closed NO fuel is recirculated!!  I've listened to the pump "tick" and I can't really tell that much of a difference if the bleed valve is cracked or not!  The ticking (pumping) really is differant (speeds up) when the bleed valve is all the way open, but what are we trying to save??
 
I'd rather have a self bleeding system with some fuel being recirculated and filtered than "save" the effort on the pump.  The new style electronic pump(vrs mechanical) is more trouble free.  I've had one for about 5 years and am well satisfied with the improved reliability. 

My thoughts.    

[Stu Jackson]

Hi, glad you asked, Mike.

Please see Ken Heyman's great thread about bleeding:  http://c34.org/bbs/index.php?topic=2884.0

What one should consider doing is "playing" with your own boat and your own system.

With our M25, I leave the bleed screw CLOSED, and I have never experienced a difference in the operation of the fuel pump ONCE THE AIR IS BLED OUT.  BEFORE it is bled out, as mentioned in the referenced thread, the pump DOES click a lot more quickly.  Once it's bled, it's tick-tick-tick, as compared to brrr-brrr-brrr.  Best I can do to explain the difference besides recording it and posting it with an audio playback.

With later engines, of which almost ALL of you qualify, there are many options.  I don't have one of those engines, so I leave it up to you.

However, and here's the gist of this message: each of you has to experiment.

Also, lest I forget, please do a search on the world "bleed" -- I promise, it won't hurt or turn red like my boat bites from this weekend have for me, but you'll learn a lot.

All the best,