Fuel return

Jrato14

Seaman
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Apr 13, 2024
Messages
74
Should Volvo gxi have a fuel return line to the tank and where would it connect to the engine
 

Jrato14

Seaman
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Apr 13, 2024
Messages
74
Sorry so I bought this boat and the fuel lines were disconnected and tanks were dry in preparation for storage. The engine is a Volvo penta gxi/e 5.0 3869255. I hooked the smaller of two hoses to the fuel pump and primed it. It ran for a little but stalled out from loosing prime. There is another hose that is slightly bigger that is coming from the fuel tank area too that is not connected to anything
 

ESGWheel

Chief Petty Officer
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Aug 29, 2015
Messages
469
I have this same motor in a 2005. There is no ‘return to the fuel tank’ line on mine. There is a high-pressure line from the pump to the fuel rail and a low-pressure return line to the pump. These lines require a special tool to remove, there are no hose clamps and one is larger than the other. There is only one line from the tank to the pump which does use a hose clamp. See this link for a diagram. The line from the fuel tank to the pump should also contain a anti siphon valve. Usually, this part is screwed into the tank and the hose is clamped on that. I expect to be doing repair work on my boat in the next couple of days and can take pictures if that will help. In the meantime, here is a video showing how to replace and prime one of these pumps which may be helpful > link.
 

dubs283

Vice Admiral
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Jul 27, 2005
Messages
5,322
There is another hose that is slightly bigger that is coming from the fuel tank area too that is not connected to anything

Possibly the fuel vent line. Can you see where it is attached at the other end?

If it is the vent line you'll want that routed proper so as to alleviate the risk of fuel vapors/raw fuel entering the bilge
 

cyclops222

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Mar 21, 2024
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1,289
2 lines to a tank might mean that your present pump is a DIY conversion pump. Never finished correctly.
 

ESGWheel

Chief Petty Officer
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Aug 29, 2015
Messages
469
Possibly the fuel vent line.
Dubs, good point I was focused on the engine side.

Jrato: The full fill ‘cap’ typically also has a vent line and the two hoses (a large fill and smaller vent) are routed to the cap. See this link for some pics and how they work.
 

BRICH1260

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Jul 6, 2011
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1,371
In addition to the fuel line in and fuel line out, there is a fuel pump cooling (water) line that has a line in and a line out.
 

Jrato14

Seaman
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Apr 13, 2024
Messages
74
Hi guys thank you so much I will be heading down to the boat later to investigate
 

Jrato14

Seaman
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Apr 13, 2024
Messages
74
The hose that I saw is actually bigger than the fuel line I will take pictures and post a bit later. Happy Memorial Day and safe boating
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,291
post pics but have never seen a return fuel line to a marine gas tank. some diesels do use a return line to the tank,
If your fuel injected, there is a cooling line but usually its never disconnected?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
49,536
Factory motor returns fuel from regulator to the fuel module.

Factory boat has 1 fuel like from the tank pickup to the filter to the low pressure pump
 

ESGWheel

Chief Petty Officer
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Aug 29, 2015
Messages
469
I was able to get back to another job on my boat today so took off the access cover for the fuel tank and took pictures. Hope this helps.

Fuel Tank lines.png

Back of Gas Cap.png
 

Jrato14

Seaman
Joined
Apr 13, 2024
Messages
74
So this is what I’m looking at on this engine it is a pain to access so pictures are not the greatest. I’m assuming the disconnected line is an old one that was never removed but I still can not get this fuel line to prime. I can pull fuel through it with a hand siphon but it doesn’t actually get going as far as feeding
 

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Bt Doctur

Supreme Mariner
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Aug 29, 2004
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19,291
you have a dual feed tank. commonly used with twin engine installations
use 1 for your motor and plug the other one
 

ESGWheel

Chief Petty Officer
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Aug 29, 2015
Messages
469
If you can pull fuel with a hand siphon pump but the fuel pump seemingly cannot, then the anti-siphon valve on the tank may be an issue or the fuel pump is.

It’s confusing that you have a dual tank set up and I am also confused as to why the tank vents have a “Y” in them > perhaps this is related to the EPA comment, unsure.

You have only one engine, correct? Suggest you validate which fuel tank you are hooking to the pump. If you cannot trace the lines, then you can disconnect each in turn at the tank anti-siphon valve and determine which one you are using with your hand siphon pump. Then change out the valve, they are cheaper than the fuel pump 😊. Make sure you hold the fuel pick up tube with a large adjustable crescent wrench when unscrewing the valve > this to preclude overstressing the pickup tube mounting. Another option is to replace (as a test) the anti-siphon valve with a similar sized barbed fitting (no internal valve). This will help narrow down the issue.
 

Jrato14

Seaman
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Apr 13, 2024
Messages
74
I actually have two engines this is the one that has the issue though the other is fine
 

ESGWheel

Chief Petty Officer
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Aug 29, 2015
Messages
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Ok so not some funky dual tank mod with a single engine. And the elevation works > i.e., if one engine can pull from its tank then the other engine should be able to as well. So back to the bad anti-siphon valve, a weak fuel pump or some sort of other blockage that your hand siphon can overcome. (The hand pump overcoming the too high of resistance of the anti-siphon valve is a form of blockage). If you know the fuel line fm the tank to the pump is good, then you can also try swapping tanks > just pull the fuel line from the ‘bad one’ and hook it to the other. Or if enough hose, swap them at the fuel pump (or put a temp splice in it). Again, this will help point to the issue. From there cleaning up the extra lines is another matter.
 

cyclops222

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Mar 21, 2024
Messages
1,289
Check valve in the squeeze bulb is jamming ?
I have never seen a squeeze bulb in any inboard engine boat. Only in O B boats.
 
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