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  • Ignition: Ignition and running rich

    I had my Carter AS rebuilt by Daytona Carbs when I rebuilt the engine. I had never run this carb before and knew nothing about it, it had been on a dead car. But I wanted to replace the RBS which was always troublesome. The truck has always run rich at speed since then, so I call Daytona Carbs about it. Fuel pressure is about 4 psi, and it it is not trickling from the venturi, so he said the float level was OK.

    Then he asked about the ignition: I said I had a rebuilt distributor with Pertronix ignition and coil, and he said "There is your problem. That and you are probably running resistor wires or plugs, or both." BTW, the only reason I changed to Pertronix is because of the poor quality points and condensers that are available.

    OK, I get both resistor wires and plugs will kill firing voltage (mine is wires only), and I have 12 volts to the ignitor and the flame thrower coil. Has anyone else heard that Pertronix can cause your engine to run rich? How? Why?
    Ron Dame
    '63 Champ

  • #2
    It's hard to imagine any ignition problem making an engine run rich.

    If the plug voltage is weak, that could lead to plug fouling, but that is not the same as running rich in my humble knowledge of how engines work.

    Rich running is too much fuel, or too little air in the fuel to air mixture.

    I have three (used to be four) Pertronix systems on Studebaker and Buick V-8 engines and they are all fine.
    RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

    17A-S2 - 50 Commander convertible
    10G-C1 - 51 Champion starlight coupe
    10G-Q4 - 51 Champion business coupe
    4H-K5 - 53 Commander starliner hardtop
    5H-D5 - 54 Commander Conestoga wagon
    56B-D4 - 56 Commander station wagon
    60V-L6 - 60 Lark convertible

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    • #3
      That's my thoughts too, I'm guessing by his well rehearsed spiel, that it was a way to avoid rework.
      Ron Dame
      '63 Champ

      Comment


      • #4
        Many thoughts, here.
        Their reply is preposterous. I wonder what they had said if you were still running points and coil. Buy a Pertronix...? I would not be too surprised if they had goofed on the fuel level.
        Isn't there any kind of restriction from the air filter? Additional vacuum can cause more fuel to be sucked by the carb.
        Is the choke fully opened when the engine is warmed?
        The best way to understand what is going on is to hook a vacuum gauge on the engine. It will tell you what happens and when.
        Are you telling about your famous 185 OHV 6? I doubt the settings of a carb designed to run a 170 CI engine could fit this one, but in this case you should be on the lean side. Was your AS coming from a 185 CI engine?
        sigpic

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        • #5
          This is indeed the 185 OHV, and I am chagrined that I've let it run this way for so long. It's a K&N filter, but even before that, it was a fresh paper filter. Choke is fully opened, fuel pressure is acceptable ( not too high) float level is OK. Since I don't know the history of the carb, I do wonder if someone had drilled out the jet at some time, that's why I called Daytona. But this guy's spiel was well rehearsed, and he did not listen. I'm still betting on jetting.
          Ron Dame
          '63 Champ

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          • #6
            Compared to the RBS, I don't know the AS that well. Isn't there a kind of additional air passage that could be clogged? If there is not, this is of course a jetting problem. Don't forget that your engine needs a good oil change now.
            sigpic

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            • #7
              Remove the main jet and measure it, there will be a number on it that denotes the size of the jet and see if they match. Jet openings do wear over size over time I had one that was that was at least half over size, but everything looked ok. I am not sure what they use as a reference, drill size or wire size. I cleaned a carb on a motorcycle and I used a drill bit to clear some debris however the drill bit was 1-2 thou over and removed some metal along with the debris. After the over hall it would not run, a new jet was installed and all was ok. It doesn't take much.
              If new jets are not available all is not lost, you can silver solder over the old ones and re-drill to the correct size. I have done this and it works just fine. For a little better economy you can re-drill slightly under size.

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              • #8
                You built an overhead valve 185? Cool. Is that build on the forum anywhere?
                RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

                17A-S2 - 50 Commander convertible
                10G-C1 - 51 Champion starlight coupe
                10G-Q4 - 51 Champion business coupe
                4H-K5 - 53 Commander starliner hardtop
                5H-D5 - 54 Commander Conestoga wagon
                56B-D4 - 56 Commander station wagon
                60V-L6 - 60 Lark convertible

                Comment


                • #9
                  Ron, your EXPERT has a few things to learn..!

                  Really guys, an ignition making an engine run rich ??! You guys must have some good drugs you're taken.
                  AND...running resistor plugs, wires, late model caps and rotors, or even spitting on the ignition...will NOT change the way the carburetor is working.

                  Many things can cause a carburetor to make an engine run rich.

                  1. Too large a main jet
                  2. Loose main jet
                  3. Too high a float level
                  4. Too high a fuel pressure
                  5. Leaking needle and seat
                  6. Power system leaking
                  7. Idle mixture too rich

                  OR...any combination of the above.
                  Plus...3psi has NOTHING to do with the adjusted float level. That's strictly a measurement.

                  Mike

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                  • #10
                    I would be checking the power valve links about now. they have been known to jam the vacuum piston full up causing rich mixture. Luck Doofus

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                    • #11
                      FWIW, I spent fifty years fiddling with carburetors. Only after getting a wide-band O2 meter did I learn how much I didn't yet know. Also, today's pump gas makes it almost impossible to get readings from spark plugs or the tailpipe. Nowadays, if the owner won't install an O2 sensor for me to connect my meter, I figure he really isn't interested in getting it right.

                      jack vines
                      PackardV8

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                      • #12
                        Not much can go wrong with a new carburetor shafts can wear and upset the mixture as can warn main jets. When the mixture is off and adjustments are made to compensate for the warn parts, is where the trouble starts. When an untrained eye or ear attempts to make adjustments usually only causes further issues. In the winter months carb ice is a common problem and no adjustment will fix it. A block heater will assist with the problem or just a longer warm up time. Vacuum leaks are frequently misdiagnosed and adjustments are frequently made to compensate only to make it worse. Carburetors and ignition systems should never have to be touched for years once they are properly set up.
                        I bought a new motorcycle 46 years ago off the show room floor and I swore to myself I would never touch the carb in any way and I never have. It developed a slight sputter once and I replaced the spark plug and it was like new. I still have it and it runs as good as the day I bought it.

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                        • #13
                          Don't forget that some people just cannot keep themselves from fiddling, disassembling, poking, prodding, and modifying. If it works, maybe I can make it work better.

                          Don't be that guy.
                          RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

                          17A-S2 - 50 Commander convertible
                          10G-C1 - 51 Champion starlight coupe
                          10G-Q4 - 51 Champion business coupe
                          4H-K5 - 53 Commander starliner hardtop
                          5H-D5 - 54 Commander Conestoga wagon
                          56B-D4 - 56 Commander station wagon
                          60V-L6 - 60 Lark convertible

                          Comment


                          • #14
                            I am a sucker for "rebuilt" carburetors at swap meets. (Especially if they're cheap.) It's partly from cheap prices, and trusting fellow club members to be true to their word. My experience has been that just about every rebuilt carburetor I have bought at a swap meet works fine once I have torn it down, rebuilt it myself, or completed and corrected the incomplete or botched job. I think one problem is that too many of us consider replacing the needle valve and accelerator pump a "rebuild."

                            If rebuilding carburetors were that simple we would probably all be carburetor experts. I have a vintage Carter metal carburetor repair toolbox that is incomplete, but if the job was so simple, there wouldn't be all the specialized tools required. Jet tools, jet seats, float gauges, and all those tiny gauge wires for clearing passages are mostly trinkets to us backyard tinkerers. And to be fair to the guys at swap meets selling "rebuilt" carburetors (especially the cheap ones)... probably is re-selling one bought from another vendor who told him it was rebuilt.

                            I admit that, when repairing a carburetor, I have been luckier than good. But, someone with the correct instructions, who can read, understand, and follow the instructions, a carburetor can be rebuilt and adjusted to provide many miles of trouble-free operation. If you can find someone really good with carburetor repair...make a friend and treat him well. They are dwindling in number just like the old relics called carburetors.
                            John Clary
                            Greer, SC

                            SDC member since 1975

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                            • #15
                              Yes, poor ignition can make your engine to 'appear' to run rich.
                              It is hard to light a fire in a cylinder.
                              That could leave unburned fuel in the cylinder, making it look like it is running rich.
                              You can see that on a dyno when the air fuel ratio goes way low.
                              Re-jetting won't solve an ignition problem.
                              If your matches are weak, your flame front might be slow or incomplete, and your campfire might just make smoke.
                              HTIH (Hope The Info Helps)

                              Jeff


                              Get your facts first, and then you can distort them as much as you please. Mark Twain



                              Note: SDC# 070190 (and earlier...)

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