fuel pump issue

This is the place to get help with technical matters concerning your M151 jeep

Moderators: rickf, raymond, Mr. Recovery

Bobtanker
civilian
Posts: 4
Joined: June 3rd, 2018, 10:25 pm

fuel pump issue

Unread post by Bobtanker » March 31st, 2021, 12:36 pm

I have a 24 volt Walbro 6000 series fuel pump installed. It has started to give me a problem. At times it will stop pumping. The pump is running but the fuel stops flowing to the carb. I thought it might be a vapor lock problem, so I installed an additional filter between the pump and the carb to allow for some expansion. This work for a few weeks and then the problem returned.
I figured out that if I remove the cover and depress the "Ball" it will begin pumping again. It takes about three minutes to fix, but losing power in traffic is bad for my blood pressure. :shock:
The fuel is new and the filters (3) are clean. The filter in the pump is clean. I can not figure out why the "ball" is getting stuck.
Any thoughts?
You do not have the required permissions to view the files attached to this post.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: fuel pump issue

Unread post by rickf » March 31st, 2021, 1:47 pm

Those pumps aren't really designed to pull a vacuum and since you are pretty high above the fuel level that could an issue. The other thing is do you have a vented cap on the gas tank and if it is a vented cap is it in the open position? It sounds like maybe the tank is not venting and it is drawing a vacuum in the tank. When you push the ball down do you hear any air go in?
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Bobtanker
civilian
Posts: 4
Joined: June 3rd, 2018, 10:25 pm

Re: fuel pump issue

Unread post by Bobtanker » March 31st, 2021, 4:19 pm

It is a vented cap and the vent is open. I hear a small clink as the ball unsticks, but I have not noticed the sound of air returning to the tank. I'll listen next time that it happens.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: fuel pump issue

Unread post by rickf » March 31st, 2021, 9:25 pm

Looking at the spec sheet here, https://www.walbro.com/wp-content/uploa ... _PS_EN.pdf, it i very confusing in a couple areas. It appears I am wrong about the lift above the tank as this says 120"?!!! That is ten feet!! I find that very hard to believe but no mater, you are only going about a foot. My main concern is fuel pressure. The carb will only handle a max of 5 lbs. and this is saying anywhere from 3 to 13 with several other sites I looked at all quoting 7 lbs.. One thing I see that may or may not pertain is the pump discharge fitting with the check valve in it. I don't think you would need that considering the height above the tank and the height of the carb above the pump, it is just too minor in my opinion but something is causing the ball to stick tight. Your best bet would be to call Walbro directly and see what they say. https://www.walbro.com/contact-us/
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Mark
Brigadier General
Brigadier General
Posts: 2085
Joined: September 19th, 2009, 11:33 pm
Location: South Dakota

Re: fuel pump issue

Unread post by Mark » March 31st, 2021, 11:01 pm

Would marvel mystery oil work?
mark


1968 m274A5
1960 m151
1981 m151A2
1964 m416
1971 m416

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: fuel pump issue

Unread post by m3a1 » April 1st, 2021, 1:33 am

Is the orientation of the pump an issue? I read (somewhere) that these pumps were happiest when horizontal.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: fuel pump issue

Unread post by rickf » April 1st, 2021, 8:52 am

They are the same orientation on all of the MEP gensets, and it is basically the same as an A1 pump which is also upright.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: fuel pump issue

Unread post by m3a1 » April 1st, 2021, 11:50 am

Ahh. Maybe they were talking about aftermarket units?

User avatar
muttguru
Colonel
Colonel
Posts: 1992
Joined: November 26th, 2007, 12:18 pm
Location: Li'l ol' England.....

Re: fuel pump issue

Unread post by muttguru » April 1st, 2021, 6:00 pm

Bob,
what model are you driving now? From the photo you posted, it looks like you have no return line back to the tank. If it's an A2, you should have. And what model of carb are you using?
Ken
Kind regards....
Ken

Always wanted - Details and pictures of M416 Trailer data plates & M151 data plates & body-tags for my research. Thanks!

Contact address - - muttguru@aol.com

Note for 2023..... Ken..."Less Stress - More Exercise!"

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: fuel pump issue

Unread post by rickf » April 1st, 2021, 6:58 pm

Ken, you of all people should know the story about the "return" line! It is NOT a fuel return line!!!!!! It is a vapor return line to prevent vapor lock. The very, very small amount of fuel that comes through that line makes no difference in any way and it can be blocked off and act just like any other carburetor.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
muttguru
Colonel
Colonel
Posts: 1992
Joined: November 26th, 2007, 12:18 pm
Location: Li'l ol' England.....

Re: fuel pump issue

Unread post by muttguru » April 2nd, 2021, 6:19 am

rickf wrote:
April 1st, 2021, 6:58 pm
Ken, you of all people should know the story about the "return" line! It is NOT a fuel return line!!!!!! It is a vapor return line to prevent vapor lock. The very, very small amount of fuel that comes through that line makes no difference in any way and it can be blocked off and act just like any other carburetor.
Rick, my ol' chum......
two things we will never agree on:-
1. unofficial shop-bought in-line fuel filters;
2. unofficial, shop-bought, electric fuel pump replacements for the original in-tank pump.

One of these items is bad enough, but both together? it's a recipe for highway disaster.
The in-line filters are poor expedients for cleaning and sealing a tank which has dirt/rust inside and electric fuel pumps that don't meet the exact specifications of the original in-tank fuel pump, and which are almost always higher-pressure, cause their own problems within the carb. Or the fuel pump eventually fails. Sometimes both !

But, as they say, "your mileage may vary" :D
Ken
Kind regards....
Ken

Always wanted - Details and pictures of M416 Trailer data plates & M151 data plates & body-tags for my research. Thanks!

Contact address - - muttguru@aol.com

Note for 2023..... Ken..."Less Stress - More Exercise!"

Bobtanker
civilian
Posts: 4
Joined: June 3rd, 2018, 10:25 pm

Re: fuel pump issue

Unread post by Bobtanker » April 2nd, 2021, 10:30 am

The fuel tank is not an A2 tank. It has been cleaned and sealed. It has a "bubba" cover where the fuel pump and filter would go on a A2 tank. A flat plate with a copper line into the tank. I have added a filter to the end of the line in the tank.
Carb is Zenith 13660. No return line to the tank.

User avatar
muttguru
Colonel
Colonel
Posts: 1992
Joined: November 26th, 2007, 12:18 pm
Location: Li'l ol' England.....

Re: fuel pump issue

Unread post by muttguru » April 2nd, 2021, 4:23 pm

Hello Bob,
thanks for the update.
Here's what I would do if I were in your shoes. But....it's your jeep...and ultimately your decision.
1. Your tank is cleaned and sealed. So get rid of that cheap, useless paper filter. If you have the gauze fuel filter in the neck of your clean, sealed fuel tank, you don't need another filter down the line.

2. That fuel pump you have is putting out too high a pressure. there are lower-pressure versions such as Facet (model 574A...but check this ref) or Facet Gold-Flo (I have a picture of it). There's also a Carter in-tank pump which I'm told fits very much like the original mil-spec pump.
I would go for the original-style Aertex mechanical A2 fuel pump but if you have vacuum wipers, that would be a further task.

3. The three versions of the Zenith 13660 carbs all have a fuel return line It's there for a reason. If the over-pressure fuel pump you are currently using is pushing too much fuel to the carb, too fast, something is going to malfunction. Most likely the nylon-mylar tip of the fuel intake needle is going to develop a groove, the result being that the needle will begin to stick in the 'closed' position and shut off the fuel. It may be worth checking the condition of the needle tip right now.

If your vehicle stops in the middle of the highway, something is wrong and it's putting your life at risk. I'm sure other folks on the board will chime in but whatever you decide to do....do something !
Ken
Kind regards....
Ken

Always wanted - Details and pictures of M416 Trailer data plates & M151 data plates & body-tags for my research. Thanks!

Contact address - - muttguru@aol.com

Note for 2023..... Ken..."Less Stress - More Exercise!"

Cobra5
Colonel
Colonel
Posts: 1528
Joined: December 5th, 2007, 11:10 pm
Location: Stevensville, Montana

Re: fuel pump issue

Unread post by Cobra5 » April 2nd, 2021, 5:22 pm

This is the pump I used in my A1 and its worked perfectly. https://www.pegasusautoracing.com/produ ... RecID=9025

I used the existing vehicle harness with the original wire that went to the in tank fuel pump, I cut the wire at the oil pressure safety switch and installed a female connector. I installed a male connector on the pump wire.
Image

Bobtanker
civilian
Posts: 4
Joined: June 3rd, 2018, 10:25 pm

Re: fuel pump issue

Unread post by Bobtanker » June 1st, 2021, 3:24 pm

Guys, here is my update. Sorry that it took so long.
I went with Cobra5's recommendation and installed a Facet pump. I have driven it about 75 miles in the past few days and it is working great (fingers crossed). Thanks for the help.
Pump1.jpg
Pump2.jpg
You do not have the required permissions to view the files attached to this post.

Post Reply