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Correct place to bleed the fuel rail?

  • Thread starter Thread starter Bob Quinn
  • Start date Start date
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Fuel is siphoni back to the tank filling the pickup line with air. Typical problems are the check valve in the racor coupled with an air leak. 90% of the time it’s the o ring on the handle of the racor. There are 2 variants of this ring one is a square the other is round. The wrong ring in the wrong cap will leak air. Whenever you change filters you should shut off the fuel selectors valves if you don’t have a valve on the inlet to the filter.
 
Fuel is siphoni back to the tank filling the pickup line with air. Typical problems are the check valve in the racor coupled with an air leak. 90% of the time it’s the o ring on the handle of the racor. There are 2 variants of this ring one is a square the other is round. The wrong ring in the wrong cap will leak air. Whenever you change filters you should shut off the fuel selectors valves if you don’t have a valve on the inlet to the filter.

I don't have the Racor brand, its a Dueler or something like that. I know I saw a flat o-ring around the large diameter, didn't notice the other one. I assume both brands would have the same setup.

When I changed the filter I didn't change the o-ring. Maybe I should. I did save it.
I think until I resolve it I might try shutting off the fuel valves when not running.

Are there any ways to diagnose where an air leak is coming from? I'm guessing not. I assume it's a matter of a process of elimination.
 
The fuel pump is a gear pump that isn’t really self priming. Air gets trapped in the pump and it can sit there and cavitate. The secondary filter is down stream of the fuel pump. I’ve had success with loosening the secondary and cranking the engine until fuel starts pouring out tightening then good to go. The “fuel rails” have a fixed orfice at the end that returns fuel to the tank. so it takes a lot of pressure to push the air and fuel back to the tank. Easier to open the secondary and bleed it out there.
 
I don't have the Racor brand, its a Dueler or something like that. I know I saw a flat o-ring around the large diameter, didn't notice the other one. I assume both brands would have the same setup.

When I changed the filter I didn't change the o-ring. Maybe I should. I did save it.
I think until I resolve it I might try shutting off the fuel valves when not running.

Are there any ways to diagnose where an air leak is coming from? I'm guessing not. I assume it's a matter of a process of elimination.

Dahl? If that's what they are they're very good filters. Better than Racors IMHO. But a little harder to get parts for.

Temporarily replacing sections of your fuel hoses with a piece of clear hose will allow you to see where fuel is clear vs having air. It's a nuisance, but it works. Also, if the air leak is before the Dahl or Dueler or whatever, air will show up coming out of the depressurizer cone in the bowl. If that is clear, then the leak is either the filter or after.
 
My boat used to have Dahls. Pita to replace elements as the whole housing has to come down instead of just pulling the top with the racors
 
Dahl? If that's what they are they're very good filters. Better than Racors IMHO. But a little harder to get parts for.

Temporarily replacing sections of your fuel hoses with a piece of clear hose will allow you to see where fuel is clear vs having air. It's a nuisance, but it works. Also, if the air leak is before the Dahl or Dueler or whatever, air will show up coming out of the depressurizer cone in the bowl. If that is clear, then the leak is either the filter or after.

Yes Dahl, thanks for the tip on tracking things down!
 
My motors have the Dahl filter in the starboard engine room, then 2 filters right by the motor.
Is this normal?
 
I have both a priming pump for both engines and port generator and a separate priming/lift pump for the starboard generator. Both are hard piped into the fuel system.

I use the priming pump primarily when changing fuel filters. it's a Walbro ... when I'm at the boat tomorrow I'll take some pics and get you a part number if you like.

I also have a cross-tie between the two engines at the secondary filter. A simple quarter-turn valve on each end. As long as i can start one engine, I can prime the other through this connection... belts and suspenders.
 
I have both a priming pump for both engines and port generator and a separate priming/lift pump for the starboard generator. Both are hard piped into the fuel system.

I use the priming pump primarily when changing fuel filters. it's a Walbro ... when I'm at the boat tomorrow I'll take some pics and get you a part number if you like.

I also have a cross-tie between the two engines at the secondary filter. A simple quarter-turn valve on each end. As long as i can start one engine, I can prime the other through this connection... belts and suspenders.

Yes, if you don't mind taking a pic that would be great! While fixing the issue would be the best thing, it sounds like it could take a lot of time to track down a pinhole air leak. That coupled with the fact that it is messy and a high risk of spilling fuel every time we change filters makes having a priming system and / or a cross tie a good idea. It would save a lot of frustration and stress for the process as well as get you up and running quickly in case of needing to prime the system in "not so ideal" conditions. I think it's a very worthwhile upgrade!

When you use this priming pump do you still need to crack a fitting loose somewhere or is it able to force fuel through the whole system somehow with out doing that?
 
I have had an issue where if I didn't shut my fuel line valves when the engine wasn't running, fuel would drain back to the tank and I would have empty filters.

I also had a fuel priming pump setup that was not functional.

Recently I found that one of the hoses involved in the fuel priming pump had cracked, and this is probably the source of my draining problem.

Anyway, I think this idea of the crossover is interesting, and I am thinking that from reading these posts that the crossover would need to be between the secondary filters, and not before the fuel pump.

Is this correct?

My priming system was plumbed in inbetween the fuel pump and the racors.

Would I be able to connect a crossover in this same location or is it best to connect it at the secondaries, and thus after the fuel pump?
 
Yes, if you don't mind taking a pic that would be great! While fixing the issue would be the best thing, it sounds like it could take a lot of time to track down a pinhole air leak. That coupled with the fact that it is messy and a high risk of spilling fuel every time we change filters makes having a priming system and / or a cross tie a good idea. It would save a lot of frustration and stress for the process as well as get you up and running quickly in case of needing to prime the system in "not so ideal" conditions. I think it's a very worthwhile upgrade!

When you use this priming pump do you still need to crack a fitting loose somewhere or is it able to force fuel through the whole system somehow with out doing that?

I've not had a priming issue yet to test that level of functionality.... However for maintenance purposes... when I change my Racor filters... I replace the filter and simply turn on the priming pump and it fills the primary fuel reservoir with fuel... another nice side feature of the system...
 
I have had an issue where if I didn't shut my fuel line valves when the engine wasn't running, fuel would drain back to the tank and I would have empty filters.

I also had a fuel priming pump setup that was not functional.

Recently I found that one of the hoses involved in the fuel priming pump had cracked, and this is probably the source of my draining problem.

Anyway, I think this idea of the crossover is interesting, and I am thinking that from reading these posts that the crossover would need to be between the secondary filters, and not before the fuel pump.

Is this correct?

My priming system was plumbed in inbetween the fuel pump and the racors.

Would I be able to connect a crossover in this same location or is it best to connect it at the secondaries, and thus after the fuel pump?

My cross-tie connection is at the secondary filters.... it's VERY simple.... two quarter-turn valves and about 12 feet of fuel hose... I'll get pics tomorrow...

FYI... I'm a 58LRC with both engines in a common engine room side-by-side. If you are a MY with separate engine rooms, then it won't be quite as easy and simple from an install perspective...but still quote doable...
 
My cross-tie connection is at the secondary filters.... it's VERY simple.... two quarter-turn valves and about 12 feet of fuel hose... I'll get pics tomorrow...

FYI... I'm a 58LRC with both engines in a common engine room side-by-side. If you are a MY with separate engine rooms, then it won't be quite as easy and simple from an install perspective...but still quote doable...

Yes I have the separate engine rooms, please show us pic's. I would be easier I think, easier than a separate priming pump. Wouldn't it be two hoses though? out from one fuel pump to the opposite filter, and visa versa?
 
Yes I have the separate engine rooms, please show us pic's. I would be easier I think, easier than a separate priming pump. Wouldn't it be two hoses though? out from one fuel pump to the opposite filter, and visa versa?

Bob-

It's a single fuel line going between the secondary filters with a quarter turn valve on each end. All you need to do to cross-tie and open both valves.

I'll put together a sketch as well....
 
My boat used to have Dahls. Pita to replace elements as the whole housing has to come down instead of just pulling the top with the racors

That's one reason they're not as popular. The other is that Racor aggressively pursued boat manufacturers for their installs. However, the big ad advantage of Dahls is that they don't trap air like a Racor. There are ways around the filter changing issue, but one has to invent their own mounting system.
 
I m a firm believer in redundancy and don’t see the point of adding fittings and hoses to the engines between the fuel pump and secondaries. It is so much easier to add an electric priming pump to each engine…
 
Thank you all for your continued help!
 
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That people would be me. And you sir are a bit offensive. It almost sounds like you are implying a lack of intelligence.</snip>

Ok snowflake

Hey guys, as a member of this board who just likes to come here and read threads to learn and somewhat live vicariously until we're ready to buy a Hatteras, can I make a small request?

Be cool. Stupid arguments are one of the reasons why I left Yacht Forums, and I really don't need to see this crap here, too.

I presume that you're both intelligent enough to receive an education high enough to secure a career that pays enough to afford these boats, so quit acting like a couple dipass 20 year olds on some Facebook group arguing about who's clapped out Civic is faster.

I'm not asking you guys to cuddle it out, but instead of fucking up what has otherwise been a very interesting thread so far, can you maybe just click on the others profile and then select the ignore option?

Life's too short for bullshit. Grab a drink, smoke a bowl, take a walk, pull your pud, do whatever you gotta do... just be cool to each other because we're all human.

I'll go back to quietly reading now. Thanks for listening.
 
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Quinn must be part of the cancel culture. Guess I’m cancelled now.

To everyone else: Why is this guy still here?

That people would be me. And you sir are a bit offensive. It almost sounds like you are implying a lack of intelligence.

What is even more "Amazing" would be that you couldn't read my post, which clearly stated this would be "Also" for priming the filter canisters after a filter change and provides redundancy.
Is that a more acceptable solution that doesn't require a snide response?

Perhaps you should hold your comments until you understand the whole situation, and by the way are we not supposed to be here to help one another, discuss ideas and solutions and generally promote a welcoming and friendly environment?

If I am missing the point of this forum someone please let me know.

What I have noticed is a long string of offensive comments from you toward other members.

If you don't like us why are you here?

If your so smart, what do you need this forum for?

To everyone else: Why is this guy still here?
 
Bob-

It's a single fuel line going between the secondary filters with a quarter turn valve on each end. All you need to do to cross-tie and open both valves.

I'll put together a sketch as well....

Bob -

Here are the pics of my cross-tie setup...

Engine Primer 01.webpEngine Primer 02.webpEngine Primer 03.webp
 

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