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How difficult (how many hours) to sync carbs?

in 912 / 914 Technical Questions 6 years ago

  • Re: How difficult (how many hours) to sync carbs?

    by » 6 years ago

    I purchased the Lockwood gauge set and have been very dissatisfied with them. The gauges are not liquid filled and the needles continue to vibrate even after the damping valves are nearly pinched off. It makes accurate readings very difficult. A friend made up his own set by using some higher quality glycerine filled gauges and they work like a charm; very steady with just a moderate amount of damping valve closure. I don't use the Lockwood gauges anymore. I don't know if the CPS gauges are liquid filled or not, but I would sure check it out first.
      
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  • Re: How difficult (how many hours) to sync carbs?

    by » 6 years ago

    I have to be honest, I bought a set just like the ones shown on the CPS website and I was not very happy with them. They didn't read the same with the same pressure connected to both and what was worse was that the difference was not constant, it changed depending on the pressure! The damping arrangement with small adjustable screws was not very satisfactory and they constantly needed tweaking. I don't know about fault-finding, but for run of the mill synchronisation I have found the Carbmate much easier to use. The adjustable sensitivity is great and the differential pressure sensor doesn't rely on the accuracy of two separate guages. I find that I can sync single-handed in about 10-20 minutes.

    I've just noticed, if you look closely at the picture on the CPS site, you can see that the two guages already disagree :-(
      
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  • Re: How difficult (how many hours) to sync carbs?

    by » 6 years ago

    I use a home-made servo, and an electronic vacuum comparator.
    5 minutes for installation of equipment and 10 minutes for balancing carburetors.
    The adjustment is done on a single carburettor, having the correct mechanical installation at the beginning on the two arms of the two carburettors.
    see the video of the servo : https://www.youtube.com/watch?v=-BIQrehwJPc
    Thank you said by: Garrett Wysocki
      
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  • Re: How difficult (how many hours) to sync carbs?

    by » 6 years ago

    Very nice Jacques, I like that!

    I made something very similar using a pair of servos. Mine has the advantage that you can adjust the idle speed as well as carrying out the balancing. The only problem with mine is that you need to modify the cable support bracket by welding/gluing one of the nuts in place and fitting a gear wheel to the knurled adjuster.

    I can sit in the safety of the cockpit and carry out the adjustment procedure. I like your limit switches, it would be more difficult for me to add those to my design. Usually I find the adjustments so small that I don't have to worry about running past the end of the screw thread.

    Here's a couple of videos of mine in operation:
    https://www.youtube.com/watch?v=91b0NNI53-M

    https://www.youtube.com/watch?v=JWri_xvak5Y
    Thank you said by: Garrett Wysocki
      
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  • Re: How difficult (how many hours) to sync carbs?

    by » 6 years ago

    I am afraid of the proximity of the propeller to make the adjustment !!
    the idea of adjusting screws with the rotating propeller does not enchant me at all, and stop the engine every time is tedious ...
    my servo installs without modifications of the installation, except a screw to be removed and then put back
    Kevin , your installation gave me ideas !
    switches limiting travel are ultimately not essential.
    the adjustment has become comfortable, just warm up the engine, connect the vacuum gauge and the servo, loosen the adjusting cable nuts on a carburettor, then start the engine and adjust with the small electrical box at different RPM, then stop the engine and tighten the nuts of the control cables. Then put the screw in place of the servo
    The electric box contains two 1.5V batteries.
    as it's easy to do, do not hesitate to check often
      
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