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Priming Racor fuel

4K views 9 replies 7 participants last post by  thevdeub 
#1 ·
I am not capable to bleed my line from the Tank to the inlet of my Racor fuel filter. Racor are supposed to be air tight , correct ?
First I tried with my manual priming pump, not a chance. but now, even with a small electric pump that works pretty good, I am only getting air.
I verified I can get fuel from the line coming out of the tank.
Now I am trying to pump from the outlet of the filter, without any luck, hoping to bleed/fill in one pass the tank line and the filter.

Is one of the gasket failing ? I opened/verified/cleaned the Racor filter and nothing seems to be blocking any of the fuel ways.
 
#4 ·
Engine is a Westerbeke 40, no lift pump, except a manual one, that seems to work fine (I can see the level in my filter go down while pumping).

Racor is a 500 FG S/S, and I paid attention to the small gasket.

I managed to push down the fuel from the tank to the filter using a small electric pump. Then this is part is fine. I can pump from the filter to fuel lines on the engine, as I can see the top level inside the filter going down while priming.

When I crank I can see some fuel at the injector on my paper rag, but nothing actually indicative of a huge pressure. more like 2"x2" spot for 5s of cranking.

At the 3 bleed point, I can get a drop by drop, relatively fast maybe 4 drops per seconds ,and no air.

However, I am pretty sure I still have air in my lines (because i switched the pump), and this air I cannot manage to bleed, doesn't matter how long I pump the manual one.

My understanding is because there is not lift pump, there should be no air at all in the system, and the pressure at the injectors should be very high.

any help appreciated.
 
#5 ·
We have a Westerbeke 58 and start by filling the Racor with fuel before we attach it. Then we use the hand pump, a button-like thing, to bleed from the primary filter to the secondary filter. Don't know if that would help with your problem. Seems to me that I an air leak into the Racor at one point and you could see a stream of bubbles when you pushed the pump.
 
#6 ·
Some progress in trouble shooting. I think I had a leak at the connector of the Racor, maybe when I created when I removed it to clean on the inside.
Now, I added my little electric pump and I can get a nice pressure in the lines.
However, based on this :

Winterizing Sea Dragon

my bleed point #1 on the pump does not bleed. Or actually, it bleeds too much. Every minute or so, if I close and open it, the pressure build and nice spring of diesel, ..and some bubbles. Eventually, it goes back to drop by drop. close the screw. start again. Must have done it like 30 times. Then I guess I have a leak, and some air is getting introduced in the circuit.

I am bleeding random points on the line, but so far, no luck.
Any trick to find it easily ?
 
#7 ·
You could try mounting your electric pump as close to the tank as possible. That way your putting pressure on the line instead of vacuum. (Don't leave it there permanently). That might let you see where the leak is. Trouble is air will leak into a smaller hole than diesel can leak out of, so this might not work either. These air leaks can be a real pain to find.
 
#9 ·
Is your filter full of fuel? Everything is filled? You mentioned the level in the filter going down as you pump, but that's not right. You should not have to bleed at the injectors after a filter change. Next time you change your filter, top it right up with clean diesel and seal it, and it may fire right up. In lieu of using pumps to charge the system. Once it's filled it should be easy to get a little stream of solid fuel and bleed out remaining air. You should not expect high pressure fuel, and would not have seen much when you cracked injector and system wasn't primed.




Sent from my iSomething using tapatalk
 
#10 ·
Thanks for all the advice.
I think I got it working now. I found at least 2 issues. The fitting between the racor and the tank line was leaking, which made impossible to pump from the tank, but allowed me to start the engine using the fuel inside the filter.
The main issue was the tiny o-ring inside the primary filter that must have felt while i changed it. there was a tiny leak at the output of the primary filter into the fuel line to the pump, and air was introduced there.

The electric pump really helped and made bleeding way easier, but now I can bleed it without it.

Now, the engine fires up and everything seems to be back as normal.

I still do not understand how that works though without a lift pump. My tank is roughly at the same height than my engine, how the fuel travels by gravity ? My racor is higher than the tank and the fuel connectors to the Racor go up (and do a half loop vertical), while I would have expect them to stay horizontal and go down.
Is it the injector pump that maintain a difference in pressure in the pipes ? does that mean that all pipes need to be air-tight, from the pump to the tank ?
 
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