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Thread: 48 - CJ2A Fuel Pump Issues

  1. #1
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    48 - CJ2A Fuel Pump Issues

    Hi,
    New member here and I have posted an introductory in the NEW MEMBER section.

    I purchased a CJ2A which seems to be in relatively OK condition (remains to be seen as I dive into it) and am working on getting it started. Previous owner said her dad used up until 2016, at which point he passed away. For the most part is has been sitting in her garage and her brothers started and ran it about once a year (thanksgiving)

    They obviously had fuel pump issues as a new fuel pump came with the purchase of the Jeep.

    As it turns out the old fuel pump was in the box and that fuel pump was already installed on the jeep.

    So at first, I worked on getting the engine popped off. Did not want it to run long as the age of the gas in the vehicle and the condition of the fuel tank was unknown.

    1) I bought a battery, hooked it up and engine spun over nicely.
    2) poured a small amount of fresh gas in carb along with starting fluid and engine fired and Backfired a little. Seemed missing on some cylinders.
    3) Checked out some basic things and found spark plug wires loose on the plugs, and more importantly loose in the distributer cap. reseated plug wires and cleaned distributer connections and pushed them back into the distributer until they clicked in place.
    4) Repeated step 2, and she fired off better, I was even able to rev it slightly by pressing accelerator pedal, but then it died when fuel in carb was depleted.
    5) I disconnected fuel line to fuel pump and connected an auxiliary tank with fresh fuel. I could not get the vehicle to run any better than above. Just died when fuel I poured in carb was burned up.
    6) I disconnected the fuel pump outlet and placed it in an empty gas can. I removed spark plugs ( so engine turns easy) Turned engine over and no fuel was pumping from the fuel pump. I found this odd as fuel pump was relatively new.
    7) I ordered a brand new fuel pump from Kaiser. Came within a couple days. I put the new pump on the jeep and repeated step 6 with input fuel from an auxiliary tank and output goin got an empty gas can. Still no fuel is being pumped by the brand new fuel pump. I am a little stumped at this point.


    Its almost like the fuel pump actuator arm is not being pushed, Is that Possible?

    My research came up with a FUEL PUMP SPACER, but I do not think mine has one. Is this required? The part right up in Kaiser sight says it is essential, however if I need it, I do not think the bolts on the fuel pump will be long enough.

    Looking for recommendations on what to check next, This seems like a very simple system, and I was shocked that putting a new pump on did not pump gas.

    NOTE - I did try priming the pump, and fuel flowed right through. ( the auxillary fuel tank was higher than the output tank. When I put the auxillary tank at about the level of the original fuel tank and the output at the height of the carb, fuel did not run through to the output . However when I cranked the engine, no fuel was pumped (The glass bowl basically remained empty except for a small amount of fuel that was there from priming it)

    What should I try next?

    PS: I read a different forum post where someone was running their fuel pump without a spacer and was getting the fuel pressure of 4 which is the recommended pressure.
    Last edited by jeep_n_john; 09-24-2021 at 07:14 PM.

  2. #2
    Super Moderator bmorgil's Avatar
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    jnj, I did see your intro. I think I remember you saying the fuel pump came with your purchase and it looked fairly new like maybe it had been used. I am wondering if it set around with a little fuel in it and the valves are ruined. It is possible to "miss" the cam lobe with the fuel pump arm. Loosen the bolts on the fuel pump so the pump can move in and out on the bolts. If the pump feels like it is "pushing" away from the block the arm is where it should be. Push the pump into the block with your hand and rotate the engine. At some point it should be pushing hard against your hand and then you should be able to rotate the engine and feel the pump move inward as the cam lobe rotates. You should be able to rotate the engine and see and feel the pump push out against your hand.

    The spacer is there to control fuel pump pressure. https://willysjeepforum.kaiserwillys...-and-pressures

    Some pumps need it and some don't. It depends on the float assembly in the carburetor. Mine runs at 4 psi without a spacer. If you are sure the line from the tank is drawing fuel from the tank, the line is not blocked and the fuel pickup is submerged in fuel, I am betting the new pump is a bad pump.
    Last edited by bmorgil; 09-25-2021 at 06:11 AM.

  3. #3
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    Updated to add Video - I could not directly load video to forum, so I had to create an album in facebook and update the video there, so I could copy the URL to put here.

    Update - Manual Test of Fuel Pump Show It works. Apparently, there is not enough vacuum to draw any fuel any distance. Removing the pump from the jeep and putting it in a test setup (see attached Video) Then priming the pump real good. I had fuel tank going into the pump so gravity fed fuel to the pump. I primed it until I got about an inch of fuel in the glass bowl. Then manually pumping the lever it pushed fuel into the outlet tank which I had setup. I had the fuel tank at about the same height as the jeep fuel tank and the outlet tank about the same level as the carburetor.

    https://www.facebook.com/1820055217/...15759136109618
    Last edited by jeep_n_john; 09-27-2021 at 11:55 AM.

  4. #4
    Super Moderator LarrBeard's Avatar
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    We can't see the video - but your description is pretty good.

    The school of hard knocks has taught us that putting a fuel filter in the suction side of the line isn't a good idea, so your comment about not enough suction is not surprising. But even so, you should be able to pull fuel through an unplugged line. On the trucks and wagons, that same pump worked through 10+ feet of fuel line.

  5. #5
    Super Moderator bmorgil's Avatar
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    jnj, it should have plenty of suction to prime itself almost immediately. It sounds like either the pump valves or diaphragm is leaking or, the fuel supply line has a restriction in it. You should not have to prime it. The pump should pull a good 4 to 5 inches of vacuum.

    You need to be sure the pump arm is making contact with the camshaft. If you can rotate the engine and find the "high spot" on the camshaft, when you try to install the pump the arm should hit the cam and hold the pump a good 1/2" away from the block. If you try to install the pump "on the cam high spot" it should be very difficult and you should have to push the pump on and compress the pump arm to get the bolts started. There isn't much to it. If the pump arm is making contact and the arm is moving with the cam, and the supply line isn't restricted (nothing on the supply line like a filter) the pump must be weak. It is possible the pump arm is bent. I cant see the video, but maybe some pictures might help.
    Last edited by bmorgil; 09-27-2021 at 10:35 AM.

  6. #6
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    Quote Originally Posted by LarrBeard View Post
    We can't see the video - but your description is pretty good.

    The school of hard knocks has taught us that putting a fuel filter in the suction side of the line isn't a good idea, so your comment about not enough suction is not surprising. But even so, you should be able to pull fuel through an unplugged line. On the trucks and wagons, that same pump worked through 10+ feet of fuel line.
    OK, I was able to add the video of my test setup. There is no fuel filter on the input side. Just a gas can and brand new fuel hose routed to the input of the fuel pump. I do not have a clamp on the setup, so it is possible that it is sucking a little air, but I really doubt it because this is brand new fuel line and goes on the fitting quite tight. The pump is not installed in the jeep, it is pumped by me by hand. Maybe I did not pump long enough to draw the fuel from the tank to the pump, but after I primed the pump and had fuel to the bowl, I could get fuel to the output reservoir. Next I will add some videos of it with the pump installed in the jeep.

  7. #7
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    OK, After the manual test showed that the pump actually pumped fuel, without disconnecting anything, I lowered the pump and slipped it into the engine. I had the plugs pulled so the engine would turn over more easily. I emptied the output bottle that had gas in it from the manual test. I then went to the jeep and cranked the motor over. At first no fuel was coming to the container, but then it started a squirt squirt squirt of fuel into the bottle. I was a little shocked as I thought the fuel would be more of a steady stream, but anyway, The pump is pumping fuel into the bottle. Here is a video of this test.

    https://www.facebook.com/1820055217/...33485798549828

  8. #8
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    Finally, I connected the fuel outlet back to the carburetor. The fuel source is still the fresh gas in the gas can (2-cycle mixed, LOL as thats all I had) I put brand new freshly gapped plugs by me into the cylinders. I poured a little gas and hit the carb with a shot of starting fluid. Jumped in the jeep, pulled the choke out and cranked the engine. It started up and stayed running when I pushed the choke in. It was missing a little and running a little rough, but it was running as long as I had my foot on the accelerator.

    Then, all of a sudden everything went quiet. I thought the engine died. Then I realized it was still running, very quietly and very smoothly. COOL. However, when I took my foot off the accelerator, it would not idle. (there is no throttle control installed on this jeep.

    I then got my phone to record a video and went through the starting process a second time. Running very quiet and smooth. However, as seen in the video, it would not idle and died when I slowly backed off the throttle. I am thinking the carb needs a clen, especially in the pilot circuit. WHat do you all think, Anything else I should check to solve the idle issue?

    Oh, I am also going to install some new spark plugs wires, and make sure all the fuel fittings are tight. I plan to inspect the gas tank and clean if necessary and replace fuel lines if needed from the gas tank to the inlet of the fuel tank. NOTE - I was able to drain the fuel tank by disconnecting the fuel line from the old fuel pump and put it in a gas can. About 2.5 gallons of skanky gas flowed out out of the onboard gas tank.

    Here is a video of it starting and running - I really wish I would have captured the first start where it was running rough and then all of a sudden switched to smooth. Wondering what was going on there if it was fuel flow or spark plug wires or something.

    https://www.facebook.com/1820055217/...78944365827166
    Last edited by jeep_n_john; 09-27-2021 at 04:39 PM.

  9. #9
    Super Moderator LarrBeard's Avatar
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    "However, as seen in the video, it would not idle and died when I slowly backed off the throttle. I am thinking the carb needs a clen, especially in the pilot circuit. WHat do you all think, Anything else I should check to solve the idle issue?"

    The spurt-spurt-spurt pump action is normal - think about an old fashioned hand pump on the well.

    The idle circuit has some very small passages and just a small fleck of crud or corrosion can block them. Just spraying and praying doesn't always clean all the passages, pushing a strand of small wire through them pushes intruders out of the passage.

    The goods news is that it looks like all of the parts are close to working!

  10. #10
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    The fuel may have flushed some crud and/or some bad gas out on the first start.
    Jeff
    '51 CJ3A
    '47 CJ2A

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