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Fuel supply

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dodjh View Drop Down
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    Posted: 08 Dec. 2022 at 9:20pm
Just finished replacing fuel sending unit and f. gauge.

Test drive up and down a 30+ grade and the engine completely died right near the top.

Full of fuel, mechanical fuel pump was primed and working...fuel tank line runs from bottom of tank through an in line fuel filter, then through the fuel pump...out and up to another in line f. filter before connecting to the carburetor.

All new lines and filters...I know these pull steeper grades then this.

I've heard electric fuel pumps can produce too much pressure and not recommended on these Willy's.

What am I missing.....?  Thanks


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Ron D View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ron D Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 9:32pm
Fuel pump pressure and volume test.

Paragraph F-35 on page 105 of the Willys Jeep Universal Service Manual.


Edited by Ron D - 08 Dec. 2022 at 10:11pm
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Mark W. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 9:39pm
An electric pump should always be used in combination with a pre-filter, pressure regulator,, and most important an oil pressure safety switch that shuts the pump off if the oil pressure drops below 5psi. My choice is a Holley Red which should be mounted at the tank with the pump head as close to the bottom of the tank. They are pushers not suckered like a mechanical. You can also add a hidden switch as a security measure.
Chug A Lug
1948 2A Body Customized
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 10:25pm
 Thanks Ron.
"COURAGE IS BEING SCARED TO DEATH
-BUT SADDLING UP ANYWAY"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 10:32pm
Where are the pre-filter, pressure regulator and oil pressure safety switch placed?

The Holly Red you suggested, does it need to be a specified pressure?

What I need is a sketch as to where everything is placed. Thanks Mark.
"COURAGE IS BEING SCARED TO DEATH
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Bruce W View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 10:37pm
  Any splices or repairs in the line from the tank to the pump can and probably will allow air to be sucked into the line instead of fuel being drawn from the tank. Hoses slipped on to steel line with no dog-knot and clamped with screw-drive clamps are notorious. Using 5/16” hose on 1/4” line, thinking the clamp will squeeze it down is worse, the clamp will pucker the hose and allow air to leak in. Overtightening the clamps makes things worse. By far the best setup is a single piece steel line from the tank to the factory-made rubber line at the pump. The inlet fitting on the pump must be tight. The gasket under the glass bowl must be in good shape and not leaking. 
  Anyone who runs two fuel filters is making a statement that he does not have faith in either one of them. 
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 11:01pm
BW, what is a dog knot?

Which size steel line should I use and what type clamps?  

Don't know if my ruber line to the pump is factory-made rubber.

Anyone who runs two fuel filters is making a statement that he does not have faith in neither one of them...I have read many posts suggesting a f.filter from tank to pump and pump to carburetor.

In any case something isn't working, so I guess I'll throw all suggestions down a stair case and start w/ the one at the bottom and work up.

I want the simpliest approach to guarantee the end of this problem.  Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote General Eisenhower Quote  Post ReplyReply Direct Link To This Post Posted: 08 Dec. 2022 at 11:42pm
I'm not sure if your tank is new and clean, but I had debris in my tank that would cause it to run like crap and then shut down, until I blew it out.
Also I don't believe ypu should have any clamps on your fuel lines. All the way to the pump and between the pump and carb should be threaded fittings, however it sounds like you have an electric pump, in that case it might be un avoidable


Edited by General Eisenhower - 09 Dec. 2022 at 12:04am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 12:03am
Tank outlet----Prefilter ----Pump----Pressure regulator-----Filter-----Carb inlet.

The best circuit for the pressure safety switch is the Holley set up.  https://documents.holley.com/199r9680-1rev.pdf

You just put a Tee in the Oil gauge line to attach the sending unit.

The back of the Riser in the body behind the Tank is a very good place to mount the pump (head down)
Chug A Lug
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1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 12:10am
Originally posted by dodjh dodjh wrote:

BW, what is a dog knot?

Anyone who runs two fuel filters is making a statement that he does not have faith in neither one of them...I have read many posts suggesting a f.filter from tank to pump and pump to carburetor.

Ok one way to see things. Another is that two filters protect two different things. The pre filter between the tank and the electric fuel pump protects the fuel pump from anything in the tank or that might come to be in the tank. I use a 40 micron steel mesh serviceable filter here. The main filter is to protect the Carburator from anything that might try to get into it including anything from the pump or the line to the carb. For this I am using a Fram Paper cartridge type filter with a 10 Micron rating again serviceable.

But then I tend to over do things that might leave my old ass walking out in the desert.
Chug A Lug
1948 2A Body Customized
1949 3A W/S
1957 CJ5 Frame Modified
Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 1:35am
[QUOTE=dodjh]BW, what is a dog knot?[QUOTE]

On a piece of steel, copper, aluminum, whatever line that is meant to have a hose connected and clamped to it, there is a “bulge” near the end of the tubing that makes the hose fit tighter. The clamp is normally placed just behind the bulge, or some prefer to put it right over the bulge. It refers to a certain part of a male dog’s anatomy. Inline fuel filters have them on both ends. 

If you filter your fuel as it leaves the tank, and your fuel system is clean, as it should be, where is anything going to get into the fuel to be filtered out before the carburetor? 

A properly connected fuel line, as original, from the tank to the pump, and the screen in the pump, WORKS. There is no need for electric pumps, or trying to out-think the original system. My fuel system is all original, with no leaks, and works from 0 mph at a hard pull to 55mph on the highway, uphill and down, from 3000 ft of elevation to 13,000 ft. What more could I ask?
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 5:58am
General Eisenhower...tank is clean, not new tho...do have clamps on the f. lines.

From tank drain outlet is threaded but has clamp on fuel line.

I don't have an electric fuel pump...was just throwing it in the mix for feedback whether it was a viable choice. Thanks
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-BUT SADDLING UP ANYWAY"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 6:26am

BW, I know what your referring to now....who carries the "bulge" lines and what size should I get?

I'm assuming the screen in the pump works, not leaking and the engine was overhauled about 60 miles ago so the cam lobe shouldn't be worn out that engages the pump lever.

So I have to figure out how to connect the fuel line w/ the bulge on one end, to the threaded piece coming from the tank, then add filter before tying into the fuel pump. 

If I understand you, then a line from F. pump outlet to carb w/o filter?
"COURAGE IS BEING SCARED TO DEATH
-BUT SADDLING UP ANYWAY"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 6:34am
 Mark, Thank you for the order of each item and link (haven't been able to open the link yet) too early in the morning for this computer or the site might be down temporarily.

Edited by dodjh - 09 Dec. 2022 at 2:48pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 11:20am
  Leaks in the inlet side of the system can leak air in without leaking fuel out. There is no pressure in that line except a tiny bit when the tank is clear full. When the fuel pump is operating, pressure inside the line is lower than atmospheric so air is always trying to push in. 
  I dont know where to buy lines with the bulge on them. Some flaring tools have the ability to make them. Again - the best, most reliable fuel system has no more joints than necessary on the inlet side, and proper joints at that. Run a one-piece steel line from the tank to the pump inlet hose, a hose with factory-made flared or pipe thread ends, and put your filter between the pump and the carb. If you create any leaks there, you will see them. A restriction (filter) in the line near the tank will only make things worse. The fuel pump will have to work harder and pressure inside the line will be even lower than normal. If you must have a filter before the pump, put it in the flex line at the pump inlet. Easier to inspect and clean or replace, too. 
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote General Eisenhower Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 2:13pm
With what Bruce said, you can pick up all new fuel lines from tank to carb for about 50 bucks depending on vendor and if you care about US made, I'd say it's worth it for the peice of mind and knowing it's done the way it's supposed to be
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ron D Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 2:30pm
Originally posted by Bruce W Bruce W wrote:

I dont know where to buy lines with the bulge on them. Some flaring tools have the ability to make them.BW 
Called a tube beading tool, it puts the "bulge" a little ways in from the end of the tube (a flaring tool puts the "bulge" right on the end of the tube).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dodjh Quote  Post ReplyReply Direct Link To This Post Posted: 09 Dec. 2022 at 3:20pm
BW...you sold me on the one filter between the pump and carb. 

My primary reason for the filter before the F.P. was to prevent any trash getting into the pump.

I'm pretty sure, the inlet side of my F.P. has a threaded female opening. If I run a one piece steel line, flared on one end w/male connector, would that remedy the air trying to push in while the pump is operating?  

What size fuel line would you use?  Thank you.


"COURAGE IS BEING SCARED TO DEATH
-BUT SADDLING UP ANYWAY"
               JOHN WAYNE








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