Puff Out Through Carb During Starting (Video)

Small Block Mopar Engine

  1. seabee

    seabee FABO Gold Member FABO Gold Member

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    Hi folks I am getting a puff of smoke out of the carb when trying to start car. Here's a short video of what is happening.

    The Long details: I just rewired the engine and charging circuit. I pulled the distributor and primed the pump since the car has not been started in awhile. I put everything back together exactly as it was since I marked the distributor and gear. I added a couple gallons of gas to the tank. I took out the plugs and let the starter turn the engine over until fuel got to the carb. Put the plugs back in and it fired up and ran great holding a steady 21 inches on the vacuum gauge. I let run for about 20 minutes it got up to it's usual 195 running temp. The engine ran great just like before I started the wiring project. The volts at the battery was 14volts and the voltage drop was .3 volts measured from the positive terminal to the voltage regulator ground. Everything seemed perfect. I shut it down.

    About ten minutes later I went to start it back up and it turned over several times then started pulsing smoke out of the carb. I pulled the plugs and everything looked normal. I let it cool down for a few hours with the plugs out then put them back in and tried to start it. It would turn over several times then pulse smoke out of the carb.

    I pulled the valve covers and turned the engine over without spark to make sure all of the rockers and valves are going up and down. They did. I then checked to make sure the rotor was pointing at #1 when at around TDC on that cylinder. It was.

    Any thoughts?

    Thanks in advance
     
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    you likely have the distributor what is known as "180 off" or 1/2 turn off, especially since you can insert the Mopar dist's two ways

    I'm not trying to lecture you........but there is no reason NOT to learn to set timing up so the engine will START without fooling with it. This is especially "handy" (and important) with such as cam break in where you want to start the engine, check oil pressure, and immediately get the RPM's up for cam break-in

    Setting the dist "for TDC" is not enough. TDC shows up but no1 only FIRES every OTHER time TDC is "up." So how to resolve this? EASY

    There are two ways to determine if no1 is on firing stroke.

    1...IF you happen to have one or both rocker covers off, bump the engine until the TDC marks are "up" and then look at the two no1 and no6 valves. One or other will be closed, the opposite cylinder will be evenly open (used to be called "split overlap."

    The two that are closed is the cylinder "ready to fire.

    2...The more popular way is to remove no1 plug, stick your finger in the hole, and bump the engine until you start to feel compression. Now look at the marks coming up and bring the marks on up NOT AT TDC but rather WHERE YOU WANT initial timing, AKA 10, 15 etc BTDC. No insert the dist, make sure the rotor points at the tower you expect, and "swing" the dist body that it has movement to advance/ retard room to set timing.

    Now, rotate dist CW (retard for SB) and slowly swing body CCW (advanced) until points open (if breaker points) or until reluctor and pickup are aligned. Check which tower rotor is "coming to" going CW and install no1 plug wire. Insert the rest and START THE ENGINE
     
    Last edited: May 22, 2021
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    • brian6pac

      brian6pac Well-Known Member

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      Yes but he said it was running for 20 min. Then he shut it off and it would not restart.
       
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      • Dana67Dart

        Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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        Was the dist tightend down?
         
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        • 67Dart273

          67Dart273 FABO Gold Member FABO Gold Member

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          (RE-reads LOL) Shit you are right. Well check the timing, ^^as Dana said^^ loose dist? How about crossed plug wires? If not check compression
           
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          • brian6pac

            brian6pac Well-Known Member

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            Exhaust valve sticking when hot ?
             
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            • seabee

              seabee FABO Gold Member FABO Gold Member

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              Yes distributor moving was first thought as well. Del, I actually did exactly what you said posted above to check for timing when I first checked....because you taught me that years ago when I actually had my distributor 180 out :lol:.

              It is definitely secure and pointing correctly but it does seem like it is igniting at the wrong time for some reason or has a valve open. When the kids go to sleep in a few I will sneak out to the garage and do a compression check and report back.
               
            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              If it was only a valve open, it would start. One valve hanging open won't keep it from running. Concentrate elsewhere.
               
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              • seabee

                seabee FABO Gold Member FABO Gold Member

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                Compression check was normal (whew).
                 
              • RustyRatRod

                RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                It's electrical, IMO. Like an MSD failure. It's not uncommon. I don't know how to test for it, though as I've always tried to steer clear of MSD stuff. I've used it in the past and worked on it for others, but I've never really cared for it. Some people swear by it and good for them. I never have. DO you have a points type distributor to throw in and just try? I bet it'll run fine then.
                 
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                • seabee

                  seabee FABO Gold Member FABO Gold Member

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                  It is one of those HEI "Ready to run" getups, which has run great for about 5 years, but I think you are on to what it is. I have a points Dist I will dig up after church tomorrow and give it a go. I appreciate all the feedback!
                   
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                  • brian6pac

                    brian6pac Well-Known Member

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                    I had a bad coil do something similar to that, do you have an other coil to try.
                     
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                    • seabee

                      seabee FABO Gold Member FABO Gold Member

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                      I dug up a points distributor and coil to give it another go. I really didn't think it would be the coil because I checked the ohms on the primary and secondary last night and they were in spec. I put the coil in first since it was the quickest and it started right up. To make sure it was the coil and not just a bad connection I put the first coil back in and it was back to no start/puff out of carb.. I rotated them in and out again and the same results. The replacement coil and the no-start coil have pretty close ohm readings .5/.8 ohms primary and 5 Kohms secondary.
                      giphy.gif
                       
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                      • RustyRatRod

                        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                        Hell yeah. Glad that was it. I've seen Del (@67Dart273 ) say there's really no definitive test for a coil, so there you go. Fantabulous. I'm really glad you got it going again. And simple, too.
                         
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                        • RustyRatRod

                          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                          Oh one more thing I would recommend. Make SURE you have the right coil for that distributor. Depending on which one it is, some require a ballast and some don't. So make sure you have that right. You don't want a repeat performance.
                           
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                          • 67Dart273

                            67Dart273 FABO Gold Member FABO Gold Member

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                            Amazing. Due to my foolin with old outboards (largely old school magneto ignition) I managed to drum up a built-for-purpose coil/ condenser tester off egag. The thing really works great. And it's true. You can NOT tell if a coil is good or bad by resistance test. you need some sort of dynamic test, something that actually puts the thing into operation
                             
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                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              Thanks, Del! I thought I remembered you preachin on that somewhere else on here.....and gettin argued with as usual. lol
                               
                            • gzig5

                              gzig5 FABO Gold Member FABO Gold Member

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                              To properly test a coil you need a megger or hipot tester. They inject high voltage into the circuit and then look for leakage due to insulation break down. We test 480v motors and VFDs at work to around 2800 volts AC.
                               
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