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Old 03-09-2019, 04:31 PM   #1
BIG BLOCK JIMMY
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No return fuel line?

My Jimmy has a mechanical fuel pump, Holly 4bbl carb and no return fuel line. As you can see in the pic, someone plugged it off. I don't know if I'm supposed to have a return or if someone before me just bought the wrong pump and modified it.
I'm thinking I DO want a return line because its running rich and has a STRONG fuel smell that I cannot figure out!
So dumb question: Can I just simply run a return line back to my tank?

Thank you!
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Old 03-10-2019, 02:48 PM   #2
hops
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Re: No return fuel line?

I'm not a pro, but a return line shouldn't be needed with a carb.
That pump configuration is for an evap emission control set up. If you think you have too much pressure, it's an incorrect pump. Change it or put a regulator before the carb.
All that being said, I would put money on the Holley needing tuned and probably rebuilt.
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Old 03-10-2019, 03:36 PM   #3
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Re: No return fuel line?

Thank you... I think the easiest thing to do is to put a pressure gauge and regulator on it as you stated. The pump looks like a $20 special and the carburator is only about a year old. I'm sure it needs tuned though.
I plan on installing an EFI system from tank to TBI in a couple months, so I'm looking for the cheapest fix I can find as I will be tossing the parts soon.
I'm filling up my daily; summit racing shopping cart now.
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Old 03-10-2019, 10:11 PM   #4
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Re: No return fuel line?

A return line IS beneficial with a carb setup. It allows the fuel to stay cool especially if the line is close to exhaust components. This will reduce chances of percolation. If you take a look at the return port on the pump, you'll notice that it is much smaller in diameter than the feed and pressure line. The rich fuel smell has nothing to do with the pump unless it's putting out more pressure than the needle and seat in the carb can handle. Just leave it as is until you convert over to EFI.
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Old 03-11-2019, 05:04 PM   #5
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Re: No return fuel line?

Yes Sir... I ordered a fuel pressure regulator, gauge and other goodies just for fun and it won't take any time to slap a return line on too.

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Old 03-30-2019, 08:50 PM   #6
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Re: No return fuel line?

So I installed new fuel lines, filter, added a return line as well as a fuel pressure regulator and gauge. The pump stayed the same. Now after a few minutes of running fuel starts leaking out of the float gaskets and other places. It did not do this before! The pressure is just under 6 PSI. It's a Holly 4160 carburetor.
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Old 03-31-2019, 11:04 AM   #7
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Re: No return fuel line?

Quote:
Originally Posted by BIG BLOCK JIMMY View Post
So I installed new fuel lines, filter, added a return line as well as a fuel pressure regulator and gauge. The pump stayed the same. Now after a few minutes of running fuel starts leaking out of the float gaskets and other places. It did not do this before! The pressure is just under 6 PSI. It's a Holly 4160 carburetor.
If it's leaking now then you got crap in the line and it got stuck between the needle and seat. Carbs are nothing but a PITA. Do yourself a favor and put EFI on it. Drive ability and economy will go up.
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Old 03-31-2019, 01:07 PM   #8
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Re: No return fuel line?

I know, I know you are 100% correct. I knew I was throwing away money but I was stubborn and wanted to solve the strong fuel smell from what I believed to be a flooding carb. I spent the money to WIN and learn...and because I wanted a cool oil filled pressure gauge.
So I learned that I lost and that I got crap in my PITA carb, lol.
I didn't want to throw $2500 towards an EFI system (new tank and everything) until I could get it down to a collision center to verify that the frame is straight and figure out why my axle assemblies are not square. But that's another thread...
I promise I will fuel inject her soon. Then I will post stupid questions about how I screwed that up.
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Old 03-31-2019, 03:45 PM   #9
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Re: No return fuel line?

Thanks Hemi43. I cleaned the needle and seat valves and that solved the problem. I also installed another filter close to the carb to help eliminate anymore "crap" from getting in there.
I haven't had a carb since 1993 and I never had to mess with that one.
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Old 03-19-2020, 11:47 PM   #10
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Re: No return fuel line?

Did you ever end up getting an EFI? Did you ever get rid of raw fuel smell? I have the same problem with my Holley carb. Want to keep it as stock looking as possible - it's the original motor but with Holley carb/intake.

Quote:
Originally Posted by BIG BLOCK JIMMY View Post
Thanks Hemi43. I cleaned the needle and seat valves and that solved the problem. I also installed another filter close to the carb to help eliminate anymore "crap" from getting in there.
I haven't had a carb since 1993 and I never had to mess with that one.
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Old 03-19-2020, 11:49 PM   #11
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Re: No return fuel line?

Which EFI did you go with? You're 100% happy? Wanting to keep mine as stock looking as possible.

Quote:
Originally Posted by hemi43 View Post
A return line IS beneficial with a carb setup. It allows the fuel to stay cool especially if the line is close to exhaust components. This will reduce chances of percolation. If you take a look at the return port on the pump, you'll notice that it is much smaller in diameter than the feed and pressure line. The rich fuel smell has nothing to do with the pump unless it's putting out more pressure than the needle and seat in the carb can handle. Just leave it as is until you convert over to EFI.
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Old 03-20-2020, 08:43 AM   #12
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Re: No return fuel line?

I bought the Holley Sniper EFI kit and bought a Boyds non-EFI gas tank. The kit comes with an external pump, etc. and for future laziness, I didn't want to have to drop the tank if I had pump issues.
All that being said, everything is still sitting nice and pretty in their respective boxes because I haven't had time to install anything yet.
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