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Thread: Slick start

  1. #1
    Gilbert Pierce's Avatar
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    Default Slick start

    Several weeks ago I commented that any day I didn’t learn something new was a wasted day. Out of necessity today I learned how Slick Start works, to trouble shoot it and wire it.
    So the day turned out to be a winner.

    I was asked by the owner of an Experimental Laser to time his left mag he had taken loose but not removed. 10 minute job right. WRONG. With the mag in place, the right mag at 25* BTDC the left could only be set about +-2.0 degrees on either side of TDC. The original start switch had been replaced with 2 SPST toggles and a start button to activate the start solenoid. While watching the Indy 500 I think I got it sorted out. Tomorrow will tell.

    The mag is a Bendix S4LN-200. Never ran into one of those dual point babies before either. I guess you shower of spark guys are familiar with these.

    Last edited by Gilbert Pierce; 05-30-2021 at 08:56 PM.

  2. #2
    Gilbert Pierce's Avatar
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    Default Re: Slick start

    NEED HELP
    All the wiring checked out.
    A little background.
    The airplane is an EAB Stephens Acro Laser with and IO 360 recently purchased by the owner.
    He has flown it about 50 hours with no issues.
    Was not happy with the automotive wiring and some other issues.
    Rewired the complete airplane. A really nice profession job with all certified aircraft materials
    He loosened the left Mag to gain clearance around some hardware. The Mag was not removed
    The Mag is a Bendix S4LN-200 with a two sets of points.
    It is wired to a Silck Start Module IAC with Slick SL2-96 page 8.
    I anticipated just attaching my buzz box and resetting the timing. The right Mag was right on.
    What I found was the I could vary the timing on the left mag from -2 to +2.
    That was with the Buzz box on the "P"(capacitor terminal) lead wire to the Left Mag off on switch
    I got the lead for the Retard points attached to the buzz box and got the same reading.
    I then isolated everything and put my buzz box on the Magneto Capacitor terminal (P Lead). Same reading.
    At this point I can only assume both sets of points are basically set zero degree (TDC) timing.
    Any thoughts or ideas on what I am doing wrong would be appreciated.
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    Last edited by Gilbert Pierce; 05-31-2021 at 05:43 PM.

  3. #3

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    Default Re: Slick start

    Hey Gilbert, I just replaced some Bendix mags, one had the retard breaker points in it, I had to use my Bendix adapters in the P lead holes, are yours terminals? There is no magic in this system, the run points need to open at the same time as the right mag, the start points open much (10 degrees on the IO-470 I did) later, the way the ignition switch is wired up the run points are grounded and the start points are feed by the output of the slick start. You can test the slick start by advancing the timing ( with all the plugs out of course!!!!!!!!!!!!!! ) until you reach start advance and then you can check the current jumping the gap on the plug! Its pretty cool! So, I would think you have a wiring issue, so disconnect both p leads and time the run points @ 25 degrees, the start points are set inside when setting the e-gap. I can PM you my Phone if you want?

  4. #4

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    Default Re: Slick start

    I much prefer Impulse magnetos! Change the spring every 500 hours!

  5. #5
    Gilbert Pierce's Avatar
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    Default Re: Slick start

    Thanks for the response.

    I use “P” lead adapters. I haven’t pulled the mag because all he did was loosen the nuts and rotated it thru the radius the slot allows. If it had been set 25* like right mag I should have been able to get it back in time without removing it.

    Guess I’ll remove it tomorrow and see what is going on. With everything disconnected from the mag it seems to me I should be able read the run points timing with only the P lead adapter connected and same for the retard breaker with P lead adapter in retard connection.
    Doing that they both read the same which makes me believe the timing was set the same for both.

  6. #6
    Vagabondblues's Avatar
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    Default Re: Slick start

    It sounds like what you are seeing is the retard point function. When you are at the firing position and the advance points are open the primary circuit is still grounded. The retard points are still closed, grounding the primary circuit preventing the coil from collapsing its field. As the engine advances towards TDC the retard points lag about 15 degrees (lag angle) from the advance points, or somewhere about 10 degrees BTDC. At that time both points are open and the primary circuit is open, which can be seen with your timing light.

    Normally the ignition switch removes the retard points from the circuit after it is released and the engine is started.. If I remember correctly SlickStart controls the retard points with an internal relay which isolates the advance points after the starter is de-energized.

    The ABCs of shower of sparks is a good description of the different systems.
    https://www.bonanza.org/contentasset...rks-system.pdf
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    Last edited by Vagabondblues; 05-31-2021 at 07:33 PM.

  7. #7

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    Default Re: Slick start

    Connect one magneto time box lead to run, the other to start, this requires 2 adapters (and mag ground of course). Should time unless something is goofy internally!

  8. #8
    Gilbert Pierce's Avatar
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    Default Re: Slick start

    After re-reading the slick start manual and several other sources and analyzing the diagram Vagabondblues sent me I concluded the RUN timing was off.
    Verified the retard points were out of the circuit with no power on the Slick Start box.
    I removed the Mag, set the red tooth in the window, 25 degrees BTDC on cylinder #1 and slid the mag back in and adjusted it slightly so Left and Right mags fire at the same time. Ran the engine today and the mag check was good.
    Should be good to go. Oh, about Bendix fuel injection........never mind...
    Last edited by Gilbert Pierce; 06-02-2021 at 03:44 PM.

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