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  • #16
    Thanks for all the replies ppl.

    OK, I'll check and see where Im pulling vac. from. If it is manifold, where should I change it to? I will check the timing as you stated to see if there is slack. If it's OK, what should be my next thing to look for?

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    • #17
      Get the carb to spit gas when you depress the gas pedal is the first challenge. Take the 1 you have back where you bought it and tell them it is NFG. To test the acc pump as long as you hold the throttle open it should stream out til it runs dry then let up on the throttle, give it a few seconds and try it again. should have refilled from the main bowl and shoot out again. All this gas is going to make it hard to start so beware.

      Vacuum should come off the carb at a point that has no vacuum at idle.

      If you plan on keeping the Jeep for a while you can change the timing set but then I would also be looking at a new oil high volume pump, pick-up and water pump etc. All will show wear but then again it all depends on how you are going to drive it and how long you intend to drive it before a full rebuild or step up. Don't let it nickle dime you.

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      • #18
        is there any other reason why the carb isnt spitting fuel as soon as you press the pedal. Is the accel. pump the only reason?

        BTW, I was checking timing again and with the vaccum attached it advances of course as you rev engine. Vac is from carb not manifold. When I undid the hose, plugged it and revved engine, the timing STILL advanced. Is this normal???? Doesnt seem like it.

        Will it help if I take some pics of the setup?

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        • #19
          USSfishkiller,
          Initial timing should be set to 5 deg BTDC with the advance hose removed and vacuum plugged for manual transmissions...idle with vacuum disconnected should be 500RPM or less. It is 10 deg for auto's, and 5 for those auto tranny's made for California. Acceptable is between 3-7 deg BTDC. Idle RPM should be set between 650 and 800. Total degree's of advance, ***uming your vacuum is working properly, and that your chain isn't stretched out, etc. is 25.6 to 33.6 deg at 2000 RPM all gizmo's hooked up.
          Last edited by gnarly; 10-13-2008, 12:45 AM.

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          • #20
            You'll see the timing advancing when you rev it with the vacuum disconnect because of the mechanical or centrifugal advance. Under load this is the only advance you'll have because under load normally you have no vacuum.

            Because your squirters work after a few pumps that the check ball may not be seating right pushing the gas back and forth into the main bowl til it seats right and you get a squirt out of it or the plunge maybe ***embled wrong. Since the carb's needle and seat is above the float level there is noway the carb would drain back to the tank and even so it should never drain from the accelerator pump bowl.

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            • #21
              Originally posted by Play400 View Post
              From what I read his initial timing is 10 degrees instead of the 5 auotzone says it should be yet my emission sticker for an 80 says 10 degress +/- 2 degrees. I don't think it is off. Do you really think a 5 degree variation is going to cause that much trouble at low rpm especially when it is still advanced not retarded? Normal timing varys from an initial of 10 to maybe a max of 50 with full vacuum and mechanical advances in puttin' easily down the road.

              quote "Sputters some times in low RPM under acceleration" Only 2 reasons for a bog here, #1 which is caused by NOT getting a squirt of fuel as soon as the throttle is moved. #2 you are using manifold vacuum as a source for vacuum advance and it is retarding when you give it gas. People go to manifold vacuum because it is easy to get the motor to idle nice but it screws up drivability. He also mentioned it was hard starting when left sitting for a few days. Timing chain gets worse from sitting?

              and to cap it off he did state that the accelerator pump was not squirting on initial pumps which you have to admit is the root cause of his hard starting and bogging.

              Lets hope he does 1 change at a time so we can find out what the fix was.
              Play400,
              I'm not discounting your post. He may very well have carb issues, fuel pump issues or timing issues. I'm saying, don't discount a slack timing chain or a fuel pump until it's been checked. All of this stuff works together.
              Last edited by gnarly; 10-13-2008, 08:35 AM.

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              • #22
                Originally posted by gnarly View Post
                Play400,
                I'm not discounting your post. He may very well have carb issues, fuel pump issues or timing issues. I'm saying, don't discount a slack timing chain or a fuel pump until it's been checked. All of this stuff works together.
                I do acknowledge that the chain etc can add to the vehicle not running or running poorly all the time but this is an intermittent problem but we also know that the chain has nothing t do with the carb spitting gas. And the fuel pump does not pump gas when the motor is not turning over so we can discard that as the reason the carb doesn't spit because numerous pumps will make it squirt. The only thing we know for sure is the carb does not work properly.

                BTW thanks for the heads up about the timing for the at. Truck has a T18 now but power came from 1 with a at thus the 10 degree initial on emission tag. But as I mentioned earlier I shot the timing at 2500 rpm for 34-36 degrees with the vacuum hose disconnected and let the initial fall where it may. Total mechanical advance is more important than initial.

                I'd like to see the carb problem fixed before addressing any other issues. Should start on 1 pump and not bog. Atleast that is the path I would take first if it was my Jeep and my $$.

                Comment


                • #23
                  Originally posted by Play400 View Post
                  I do acknowledge that the chain etc can add to the vehicle not running or running poorly all the time but this is an intermittent problem but we also know that the chain has nothing t do with the carb spitting gas. And the fuel pump does not pump gas when the motor is not turning over so we can discard that as the reason the carb doesn't spit because numerous pumps will make it squirt. The only thing we know for sure is the carb does not work properly.

                  BTW thanks for the heads up about the timing for the at. Truck has a T18 now but power came from 1 with a at thus the 10 degree initial on emission tag. But as I mentioned earlier I shot the timing at 2500 rpm for 34-36 degrees with the vacuum hose disconnected and let the initial fall where it may. Total mechanical advance is more important than initial.

                  I'd like to see the carb problem fixed before addressing any other issues. Should start on 1 pump and not bog. Atleast that is the path I would take first if it was my Jeep and my $$.

                  We are "square", or shall I say "round". My last fuel pump was bad. The check valve in the thing went bad and gravity was pulling the fuel back to the tank. I had a huge jump in pressure between pump cycles. It was always harder to start after it sat a while until I replaced it. In addition, it would lag after initial start while it filled the drained line, but I agree, the carb should pull the fuel already in the bowl as you mention. I bow to your carb savy, and wish I had the same.

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                  • #24
                    Well, I suppose you guys are saying I should move timing to 5 BTDC. Could my distr. be bad?

                    I still don't see why it takes several attempts to start. Lets say I pump the pedal until gas DOES squirt out. Should it start right up? If so, and it doesn't; would that still mean a carb issue?

                    Hell, why don't I just go ahead and go EFI.

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                    • #25
                      Try this cold...

                      Open the choke and pour a bit of gas into the carb. Pump the linkage once to close the choke. The choke flap should seal the top of the carb all away around. With the choke flap closed start the truck. You may have to hold the gas pedal down but do not pump it. Once it catches treat it like a flooded carb. Should start easy like that.

                      FYI I just recently changed my kid's Jeep over to an electric choke. Used the transfer case indicator power lead as the source. Truck ran like crap, sputtering, stalling etc. Today I checked it out and choke wasn't opening past the pull-off but voltages checked out ok???????? Got #$% off and put a relay in and apply direct battery power. For what ever reason choke works properly now. Was wondering if I originally had a bad connection so went back to the old config. Problem back. Don't know why. Could it be I wired it in series? Ground , choke, light bulb, power???? Something else for you to check.
                      Last edited by Play400; 10-13-2008, 06:51 PM.

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                      • #26
                        I have an electric choke also, and when its hot it does open all the way (vertical). when its cold, it is shot but but if you open it, it just springs back to closed. doesnt stay there. I talked to someone else that said the pedal shouuld make it move. but its not. should I check it when its hot to see if i press the pedal it closes. Ill check my power source also to see where its coming from..i dont remember.

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                        • #27
                          Originally posted by USSfishkiller View Post
                          I have an electric choke also, and when its hot it does open all the way (vertical). when its cold, it is shot but but if you open it, it just springs back to closed. doesnt stay there. I talked to someone else that said the pedal shouuld make it move. but its not. should I check it when its hot to see if i press the pedal it closes. Ill check my power source also to see where its coming from..i dont remember.
                          If you hold the gas pedal or linkage wide open the choke plate will open a bit. Throttle has to be wide open. It is a mechanical over ride. From what you described the chock is working fine. And since it works right I wouldn't bother checking the power source.

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                          • #28
                            ok, well i still need to check the chain. how can you check the fuel pump?

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                            • #29
                              You have to put a pressure gauge in line. You can pick them up anywhere like autozone or advanced. Put the pressure gauge on the output side of the fuel line after the fuel pump. I believe the range is 5 to 6.5 psi for 8 cylinder engines and 4 to 5 psi for six cylinders. If that test works for you, there are other tests you can do. You can Volume test and Vacuum Test. Let me know if you need that information. I'll photocopy the tech manual or something.


                              While you are there, pull the fuel pump, It only has a couple of bolts. Take care when removing the last bolt and note the position of the pump arm on the lobe. You will feel spring tension if you stopped the motor on the pumping stroke. Be sure to put it back the way you found it. After removing the pump, just push it to the side, and stick your finger in there towards the block. You will find the chain with a little stretch if you have average sized hands.

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                              • #30
                                ok ill try that.
                                BTW, is there a way know when my engine was made. The jeep didn't come with the 304 and Id like to know a year.

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