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Hot Start Issue A65

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  • Hot Start Issue A65

    My engine is very hard to start after running even as little as 5 or 10 minutes.
    I would like to hear some thoughts from the tribe. I have the old style mags.

    It will start if the throttle is open about 1/2 but I can't do that alone.
    Wayne Melvin
    N43112

  • #2
    Re: Hot Start Issue A65

    That is typical with the old style Bendix mags. I have a some rules I follow for starting the engine hot. I never let someone else prop it for me unless I know they know how to do it right. I have someone hold the tail or brakes. If no one is around the tail must be tied down. No priming or blades pulled through. Mags hot throttle cracked for about 800RPM. Make sure you give it a quick hard pull (speed is important). It will usually start the first blade, if not it is a struggle to get it started. Other things that will help are new coils and condensers in the mags, also you could have the magnets recharged. Other than that switching to mags with impulse couplings is one other choice.Tom

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    • #3
      Re: Hot Start Issue A65

      Typical for magnetos with weak coils. When hot they produses a weak or no spark at low RPM like at start. Rebuild with new coils or by new Slicks!
      It works like this: Pay with a smile and be home for supper.
      Keeps the wife smiling and you flying!(;f Len
      I loved airplane seens I was a kid.
      The T- craft # 1 aircraft for me.
      Foundation Member # 712

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      • #4
        Re: Hot Start Issue A65

        Wayne,

        Try shutting the engine down per Continentals instructions. As you shut the mags off open the throttle briskly all the way. I was having problems too, which I found out was the engine was overly rich after trying to restart after shutdown. With the throttle closed it allows fuel to pull through allowing the engine to reprime itself. By opening the throttle it accomplishes a couple of things, clearing the carb out and cooling the cylinders to prevent the engine from detonating from any hot carbon deposits, etc. This is a simplistic answer, and I'm shooting from the cuff on this because I'm too lazy right now to go look, but I know I have read this in several locations. It worked for me and now hot starts a cinch. Don't know a thing about the mags, though.
        Cheers,
        Marty


        TF #596
        1946 BC-12D N95258
        Former owner of:
        1946 BC-12D/N95275
        1943 L-2B/N3113S

        Comment


        • #5
          Re: Hot Start Issue A65

          Originally posted by Wayne View Post
          My engine is very hard to start after running even as little as 5 or 10 minutes.
          I would like to hear some thoughts from the tribe. I have the old style mags.

          It will start if the throttle is open about 1/2 but I can't do that alone.
          Wayne! 100LL or car gas? My C-85 on 100LL was difficult to start "hot"...throttle to the wall and be quick... With car gas,throttle to idle and first flip...

          Jim
          Jim Hartley
          Palmer,Alaska
          BC12-D 39966

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          • #6
            Re: Hot Start Issue A65

            Even though I have fresh newer Bendix on mine it's prone to flooding when hot. The cause is from the fuel in the runners condensing and puddling in the spider etc. As soon as the engine starts it gulps up a ton of fuel and is flooded. My fix has been this. Plan to turn the fuel off on the taxy back to the parking area and run the carb out of fuel. As it dies apply full throttle. Turn mags off and throttle back to idle before getting out.
            On startup I just crack the fuel valve open for 2 seconds and then off again. Mag on, throttle at idle or a touch more and it will start on the second or third blade and stay running. Turn fuel on and you're good to go. Never had a problem since in two years with this technique.
            Another solution could be to turn the backwards 7 blades prior to starting to clear raw fuel out.
            Ron

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            • #7
              Re: Hot Start Issue A65

              Thanks for the replys guys. Some great info here. I would really like to have the new mags but not in the budget at this time. I'll try this info this weekend.
              Wayne Melvin
              N43112

              Comment


              • #8
                Re: Hot Start Issue A65

                Wayne,
                It seems like every one of these little engines have a uniqueness of their own when it comes to starting. The weak coil theory may have some merit, but there are a couple of other possibilities. As point cams wear the timing of the mag will change. If the points are opening late enough the magnet will have passed it's point of greatest strength (E gap) and lead to a weak spark. This is most prevelant at low (or no) rpm and will still likely give you an acceptable mag check at 1500 rpm. Each of the mags is timed at a different point BTC (I think the RH is later timing) and sometimes starting on just that mag will help the hot starts, although this type problem is usually indicated by the engine kicking back while propping it. If the engine does not run fairly smoothly at idle RPM on either mag the internal timing of that mag may be off enough to complicate starting. This is something that will develop slowly over the life of the cam. If you are able to consistently start at 1/2 throttle you problem may be fuel related. If you are getting fuel dripping out of the carb, or consistently flooding you could have a worn needle valve/seat in the carb. Turn your fuel on and see if it starts dripping on its own after a few minutes. If you have the old style steel needle (some folks recommend this for auto fuel) there's not much you can do except remember to turn off the fuel each time you shut down or change to the newer neoprene type needle. Good luck, and now you realize why your arms are so sore!

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                • #9
                  Re: Hot Start Issue A65

                  Wayne,

                  I meant to ask, did they get the new building up yet? This was such a nice airport to visit last year. I still am impressed with the white fence around the airport. Nice touch. Good luck, I know I wore myself out trying to start the engine hot until I found the technique.
                  Cheers,
                  Marty


                  TF #596
                  1946 BC-12D N95258
                  Former owner of:
                  1946 BC-12D/N95275
                  1943 L-2B/N3113S

                  Comment


                  • #10
                    Re: Hot Start Issue A65

                    I really appreciate the responses from everyone. I have my work cut out for me Saturday.
                    Wayne Melvin
                    N43112

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                    • #11
                      Re: Hot Start Issue A65

                      I used to have the same problem, but now I flip the prop back 5 or six blades, then crack the throttle to give me 800 RPM. works every time. Brie

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                      • #12
                        Re: Hot Start Issue A65

                        not in the budget? Try one mag, works like a charm and the old mag is a spare
                        B 52 Norm
                        1946 BC12-D1 Nc 44496
                        Quicksilver AMPIB, N4NH
                        AOPA 11996 EAA 32643
                        NRA4734945
                        Lake Thunderbird , Cherokee Village
                        Somewhere on the 38° parallel in NE Arkansas

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                        • #13
                          Re: Hot Start Issue A65

                          I have new Slick Mags on my A65-8.. I have been experimenting with hot starts..I find that with the throttle closed and two hard pulls it starts every time....cold starts require two shots of prime, pull it thru about six times,switch off and it starts on the first pull.
                          Walter Hake TF#

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