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efraim.otero(at)gmail.com
Guest

Posted: Tue Nov 03, 2020 9:28 am Post subject: Magnetos

Dear All:I wanted to see if I could get inputs to understand an issue I am having with my Bendix magnetos.

My biplane, an O 200 powered Fisher Celebrity has what I call a partial Electric system. One 12 V 18 Ah battery that connects directly to a skytec starter. This starter has a switch that in turn leads to a starter pushbutton. 

It also has a key switch for the magnetos: Off, Left, right, both.

I tried to start the engine and it motors while pushing the starter pushbutton, with the starter switch on and magnetos on both. However the engine does not catch. 

Also, if I turn the mags off, the engine also motors but obviously does not ignite.

What might be going on? 

-Battery issues? not enough charge/power?

-Mag issues? not getting any spark (Should the engine be turning at some specific revs on cranking for it to generate a spark?

-Ignition harness?

-Spark plugs?

Any suggestions as to how to troubleshoot?

I am getting fuel to the engine as I can smell it. It has no fuel pump, justgravit feed. Starter motors slowly, although it does not "seem un normal" (purely perception of mine!)

Please advise,

Efraim

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Tue Nov 03, 2020 10:00 am Post subject: Re: Magnetos

Possible magneto impulse coupling failure?

_________________
Joe Gores

cluros(at)gmail.com
Guest

Posted: Tue Nov 03, 2020 10:43 am Post subject: Magnetos

My advice would be to have a mechanic troubleshoot.



In the meantime, is this a new installation that has never run or is this a new problem? 

On Tue, Nov 3, 2020 at 9:37 AM Efraim Otero <efraim.otero(at)gmail.com (efraim.otero(at)gmail.com)> wrote:



 	  Quote: 	
		  Dear All:I wanted to see if I could get inputs to understand an issue I am having with my Bendix magnetos.

My biplane, an O 200 powered Fisher Celebrity has what I call a partial Electric system. One 12 V 18 Ah battery that connects directly to a skytec starter. This starter has a switch that in turn leads to a starter pushbutton. 

It also has a key switch for the magnetos: Off, Left, right, both.

I tried to start the engine and it motors while pushing the starter pushbutton, with the starter switch on and magnetos on both. However the engine does not catch. 

Also, if I turn the mags off, the engine also motors but obviously does not ignite.

What might be going on? 

-Battery issues? not enough charge/power?

-Mag issues? not getting any spark (Should the engine be turning at some specific revs on cranking for it to generate a spark?

-Ignition harness?

-Spark plugs?

Any suggestions as to how to troubleshoot?

I am getting fuel to the engine as I can smell it. It has no fuel pump, justgravit feed. Starter motors slowly, although it does not "seem un normal" (purely perception of mine!)

Please advise,

Efraim

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Tue Nov 03, 2020 11:32 am Post subject: Magnetos

On Tue, Nov 3, 2020 at 11:37 AM Efraim Otero <efraim.otero(at)gmail.com (efraim.otero(at)gmail.com)> wrote:



 	  Quote: 	
		  Dear All:I wanted to see if I could get inputs to understand an issue I am having with my Bendix magnetos.

My biplane, an O 200 powered Fisher Celebrity has what I call a partial Electric system. One 12 V 18 Ah battery that connects directly to a skytec starter. This starter has a switch that in turn leads to a starter pushbutton. 

It also has a key switch for the magnetos: Off, Left, right, both.

I tried to start the engine and it motors while pushing the starter pushbutton, with the starter switch on and magnetos on both. However the engine does not catch. 

Also, if I turn the mags off, the engine also motors but obviously does not ignite.

What might be going on? 

-Battery issues? not enough charge/power?

-Mag issues? not getting any spark (Should the engine be turning at some specific revs on cranking for it to generate a spark?

-Ignition harness?

-Spark plugs?

Any suggestions as to how to troubleshoot?

I am getting fuel to the engine as I can smell it. It has no fuel pump, justgravit feed. Starter motors slowly, although it does not "seem un normal" (purely perception of mine!)

Please advise,

Efraim 



	




If the impulse coupler is working, and you have a combustible mixture in the cylinder, the engine should fire as the piston passes top dead center, even if the prop is barely moving. You can troubleshoot the impulse-coupled mag by: 

1. remove ALL the spark plug wires, and at least one plug from each cylinder (safety)

2. screw the plugs onto the plug wires for the impulse mag, and make sure the shell of the plugs is touching the engine.

3. switch on the impulse mag. if you're not absolutely sure which side is the impulse mag, turn the mag switch to 'both' to ensure that the impulse coupled mag is hot.

4. rotate the prop, and watch the plugs each time the impulse coupler fires (makes a sharp 'clack' sound). 

One plug should spark each time the impulse coupler fires. Continue to rotate the prop, watching the plugs, until you've heard at least 8 'clacks' (enough to fire each plug twice).

If you get no spark on any of the plugs attached to the impulse mag, either the mag is grounded, or something inside the mag is defective. It's remotely possible that all 4 plug wires are bad, or all 4 plugs are bad, but that's not where I'd start.

All the above assumes that this is a 'new' problem; that the engine has recently been running OK. If you're running mogas (at least here in the USA), know that if fuel has been sitting in the fuel bowl of the carb for more than a couple of weeks, the engine will be very hard to start until all the stale fuel is pumped out of the bowl, and fresh gas fills the bowl. (Ask me how I know this....)

Charlie

_________________
Charlie

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Tue Nov 03, 2020 12:57 pm Post subject: Magnetos

All good advice. The left mag is normally the impulse mag. So for the 

test only activate the left mag. If nothing try again with only right 

mag on. Note, engine will crank faster with a plug out of each cylinder.

Voltage only matters to starter, not to mags, as they don't get any 

battery power. If you hear noticeable slowing in the cranking, time to 

recharge the battery.



On 11/3/2020 12:21 PM, Charlie England wrote:

 	  Quote: 	
		   

 

 On Tue, Nov 3, 2020 at 11:37 AM Efraim Otero <efraim.otero(at)gmail.com 

 <mailto:efraim.otero(at)gmail.com>> wrote:

 

     Dear All:

     I wanted to see if I could get inputs to understand an issue I am

     having with my Bendix magnetos.

     My biplane, an O 200 powered Fisher Celebrity has what I call a

     partial Electric system. One 12 V 18 Ah battery that connects

     directly to a skytec starter. This starter has a switch that in turn

     leads to a starter pushbutton.

     It also has a key switch for the magnetos: Off, Left, right, both.

     I tried to start the engine and it motors while pushing the starter

     pushbutton, with the starter switch on and magnetos on both. However

     the engine does not catch.

     Also, if I turn the mags off, the engine also motors but obviously

     does not ignite.

     What might be going on?

     -Battery issues? not enough charge/power?

     -Mag issues? not getting any spark (Should the engine be turning at

     some specific revs on cranking for it to generate a spark?

     -Ignition harness?

     -Spark plugs?

     Any suggestions as to how to troubleshoot?

     I am getting fuel to the engine as I can smell it. It has no fuel

     pump, justgravit feed. Starter motors slowly, although it does not

     "seem un normal" (purely perception of mine!)

 

     Please advise,

     Efraim 

 

 

 If the impulse coupler is working, and you have a combustible mixture in 

 the cylinder, the engine should fire as the piston passes top dead 

 center, even if the prop is barely moving. You can troubleshoot the 

 impulse-coupled mag by:

 

 1. remove ALL the spark plug wires, and at least one plug from each 

 cylinder (safety)

 2. screw the plugs onto the plug wires for the impulse mag, and make 

 sure the shell of the plugs is touching the engine.

 3. switch on the impulse mag. if you're not absolutely sure which side 

 is the impulse mag, turn the mag switch to 'both' to ensure that the 

 impulse coupled mag is hot.

 4. rotate the prop, and watch the plugs each time the impulse coupler 

 fires (makes a sharp 'clack' sound).

 

 One plug should spark each time the impulse coupler fires. Continue to 

 rotate the prop, watching the plugs, until you've heard at least 8 

 'clacks' (enough to fire each plug twice).

 

 If you get no spark on any of the plugs attached to the impulse mag, 

 either the mag is grounded, or something inside the mag is defective. 

 It's remotely possible that all 4 plug wires are bad, or all 4 plugs are 

 bad, but that's not where I'd start.

 

 All the above assumes that this is a 'new' problem; that the engine has 

 recently been running OK. If you're running mogas (at least here in the 

 USA), know that if fuel has been sitting in the fuel bowl of the carb 

 for more than a couple of weeks, the engine will be very hard to start 

 until all the stale fuel is pumped out of the bowl, and fresh gas fills 

 the bowl. (Ask me how I know this....)

 

 Charlie

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

stuart(at)stuarthutchison
Guest

Posted: Tue Nov 03, 2020 2:20 pm Post subject: Magnetos

For safety’s sake, I think it’s worth clarifying some potential aspects of your setup Efraim.

Normally a rotary Off, Left, Right, Both switch also has a Start position, which momentarily grounds the Right magneto as long as the switch is in the ’Start’ position.  I you have a separate start button (which is not likely to ground the Right magneto), then be very certain whether or not your Right magneto also has an impulse coupling to retard the spark(s).  If it does, then by all means start on Both.  If not, you only ever want to be starting the engine on Left magneto.  This ensures the Right magneto is grounded and cannot fire the plugs well before Top Dead Centre (TDC), which can cause engine kick-back and damage the gearbox and accessories or worse, you if you happen to be hand-swinging the engine.  Some Bendix magnetos have a tab inside the capacitor cover that grounds the magneto when the P-lead is removed, but if you disconnect the magnetos P-leads for any reason there is real potential for the magnetos to be LIVE and dangerous.  Don’t forget that magnetos generate their own spark independent of whether the electrical system is on or off, so the only way to stop them working is by grounding the magneto circuit via the 'P-lead’ and switch, which must be maintained in good condition for obvious reasons.

V/r Stuart

 	  Quote: 	
		   On 4 Nov 2020, at 7:48 am, Kelly McMullen <kellym(at)aviating.com> wrote:

 All good advice. The left mag is normally the impulse mag. So for the test only activate the left mag. If nothing try again with only right mag on. Note, engine will crank faster with a plug out of each cylinder.

 Voltage only matters to starter, not to mags, as they don't get any battery power. If you hear noticeable slowing in the cranking, time to recharge the battery.

 On 11/3/2020 12:21 PM, Charlie England wrote:

> On Tue, Nov 3, 2020 at 11:37 AM Efraim Otero <efraim.otero(at)gmail.com <mailto:efraim.otero(at)gmail.com>> wrote:

>    Dear All:

>    I wanted to see if I could get inputs to understand an issue I am

>    having with my Bendix magnetos.

>    My biplane, an O 200 powered Fisher Celebrity has what I call a

>    partial Electric system. One 12 V 18 Ah battery that connects

>    directly to a skytec starter. This starter has a switch that in turn

>    leads to a starter pushbutton.

>    It also has a key switch for the magnetos: Off, Left, right, both.

>    I tried to start the engine and it motors while pushing the starter

>    pushbutton, with the starter switch on and magnetos on both. However

>    the engine does not catch.

>    Also, if I turn the mags off, the engine also motors but obviously

>    does not ignite.

>    What might be going on?

>    -Battery issues? not enough charge/power?

>    -Mag issues? not getting any spark (Should the engine be turning at

>    some specific revs on cranking for it to generate a spark?

>    -Ignition harness?

>    -Spark plugs?

>    Any suggestions as to how to troubleshoot?

>    I am getting fuel to the engine as I can smell it. It has no fuel

>    pump, justgravit feed. Starter motors slowly, although it does not

>    "seem un normal" (purely perception of mine!)

>    Please advise,

>    Efraim If the impulse coupler is working, and you have a combustible mixture in the cylinder, the engine should fire as the piston passes top dead center, even if the prop is barely moving. You can troubleshoot the impulse-coupled mag by:

> 1. remove ALL the spark plug wires, and at least one plug from each cylinder (safety)

> 2. screw the plugs onto the plug wires for the impulse mag, and make sure the shell of the plugs is touching the engine.

> 3. switch on the impulse mag. if you're not absolutely sure which side is the impulse mag, turn the mag switch to 'both' to ensure that the impulse coupled mag is hot.

> 4. rotate the prop, and watch the plugs each time the impulse coupler fires (makes a sharp 'clack' sound).

> One plug should spark each time the impulse coupler fires. Continue to rotate the prop, watching the plugs, until you've heard at least 8 'clacks' (enough to fire each plug twice).

> If you get no spark on any of the plugs attached to the impulse mag, either the mag is grounded, or something inside the mag is defective. It's remotely possible that all 4 plug wires are bad, or all 4 plugs are bad, but that's not where I'd start.

> All the above assumes that this is a 'new' problem; that the engine has recently been running OK. If you're running mogas (at least here in the USA), know that if fuel has been sitting in the fuel bowl of the carb for more than a couple of weeks, the engine will be very hard to start until all the stale fuel is pumped out of the bowl, and fresh gas fills the bowl. (Ask me how I know this....)

> Charlie

EfraimOtero

Joined: 04 Nov 2020
Posts: 6
Location: Bogota Colombia South America

Posted: Thu Nov 26, 2020 3:12 pm Post subject: Re: Magnetos

 	  cluros(at)gmail.com wrote: 	
		  My advice would be to have a mechanic troubleshoot.



In the meantime, is this a new installation that has never run or is this a new problem? 



It is an old setup. With a new/charged battery it fired easily. I have to point out that I live in the Andes mountains at 8,535 feet field elevation! 



On Tue, Nov 3, 2020 at 9:37 AM Efraim Otero <efraim> wrote:



 	  Quote: 	
		  Dear All:I wanted to see if I could get inputs to understand an issue I am having with my Bendix magnetos.

My biplane, an O 200 powered Fisher Celebrity has what I call a partial Electric system. One 12 V 18 Ah battery that connects directly to a skytec starter. This starter has a switch that in turn leads to a starter pushbutton. 

It also has a key switch for the magnetos: Off, Left, right, both.

I tried to start the engine and it motors while pushing the starter pushbutton, with the starter switch on and magnetos on both. However the engine does not catch. 

Also, if I turn the mags off, the engine also motors but obviously does not ignite.

What might be going on? 

-Battery issues? not enough charge/power?

-Mag issues? not getting any spark (Should the engine be turning at some specific revs on cranking for it to generate a spark?

-Ignition harness?

-Spark plugs?

Any suggestions as to how to troubleshoot?

I am getting fuel to the engine as I can smell it. It has no fuel pump, justgravit feed. Starter motors slowly, although it does not "seem un normal" (purely perception of mine!)

Please advise,

Efraim

_________________
EfraimOtero
Fisher Celebrity EX N500BC
O200 COntinental

EfraimOtero

Joined: 04 Nov 2020
Posts: 6
Location: Bogota Colombia South America

Posted: Thu Nov 26, 2020 3:26 pm Post subject: Re: Magnetos

Hello everyone! Many thanks for the input. I will give these tests a shot. For now, I have ordered a new battery to have enough cranking power. I hope this is the case. 

I apologize for answering so late but I forgot my old username and had to unsubscribe and re subscribe.

You can now reach me at username EfraimOtero.



When I get my new earthX battery I will crank and let you know my findings.

Ordered from Aircraft Spruce and should get it soon down here!

Cheers



E

_________________
EfraimOtero
Fisher Celebrity EX N500BC
O200 COntinental

EfraimOtero

Joined: 04 Nov 2020
Posts: 6
Location: Bogota Colombia South America

Posted: Sat Dec 26, 2020 8:32 pm Post subject: Re: Magnetos

It’s me again! I got my earthX battery and it really cranks! I also bought and installed new REM 40 spark plugs but again, no engine start! I will try the test suggested by Charlie England and see nor that goes!removing spark plugs and cranking with them toiuching the engine. I suspect the wire harness because I do hear the sharp clacking sound...

We’ll see...

_________________
EfraimOtero
Fisher Celebrity EX N500BC
O200 COntinental

racerjerry

Joined: 15 Dec 2009
Posts: 202
Location: Deer Park, NY

Posted: Sun Dec 27, 2020 4:21 am Post subject: Re: Magnetos

Efraim, I hear your frustration.  



Once upon a time, when an elusive ignition problem was plaguing me, I got pissed and made a spark test fixture out of a section of aluminum angle material with (6) 18mm tapped holes to which (4) old spare spark plugs were installed.   Magneto leads were temporarily removed from upper spark plugs and installed on the test fixture spark  plugs.



The aluminum angle & plugs were grounded to the engine and situated where I could easily observe sparks with the business end of the plugs pointing directly at me.  Remember that you are only going to see a spark if it comes from a magneto that has an impulse coupling.



As was said, you only need three things for combustion:  FUEL / COMPRESSION / IGNITION.  On old cars, it was easy to check for a fuel problem with a squirt of starting ether down the carburetor.  I don't recommend that unless extreme frustration sets in.   Just prime the heck out of the carburetor and if you can smell fuel, you can assume fuel supply is good.



ALSO, since this is an experimental airplane, you may be using a non-standard ignition switch(s).  "ON" in a normal switch usually means continuity across the switch, which would ground out the magnetos, disabling them.  I suggest, for test purposes, temporarily remove the  magneto grounding leads.  BE CAREFUL -  ASSUME THE ENGINE WILL FIRE UP AT FULL POWER.  Make sure the tail is SECURELY tied down and that you can easily shut down the engine by turning off fuel supply.  CHOCKS are USELESS here.



Hope this helps.



Jerry King

_________________
Jerry King

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 28, 2020 2:41 pm Post subject: Magnetos

At 10:32 PM 12/26/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "EfraimOtero" <efraim.otero(at)gmail.com>



 It’s me again! I got my earthX battery and it really cranks! I also bought and installed new REM 40 spark plugs but again, no engine start! I will try the test suggested by Charlie England and see nor that goes!removing spark plugs and cranking with them toiuching the engine. I suspect the wire harness because I do hear the sharp clacking sound...

 We’ll see... 	


    It's unlikely that a whole harness bad . . . and

    one or two bad wires would still give you some

    activity on the remaining cylinders.



    There are other maladies that can befall a magento

    rendering it completely silent: There are points

    that require proper continuity and gap. There

    is a coil. There is a capacitor.



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

racerjerry

Joined: 15 Dec 2009
Posts: 202
Location: Deer Park, NY

Posted: Wed Dec 30, 2020 4:18 am Post subject: Re: Magnetos

Efraim, 

In order to simplify things, lets try to isolate the magnetos to see if they are EVER actually producing a spark.  First, pull all the top spark plugs to insure there is NO COMPRESSION and no possibility of injury with the engine suddenly coming to life.  With all spark plugs removed, reconnect all ignition leads and lay the plugs on top of each cylinder and insure that each plug is electrically grounded to the engine.  Try to aim the sparking end of the plugs outward and to each side, so that a relatively weak spark can be easily observed.  



View one side or one bank of cylinders at  a time. That way you don't have to completely remove and reroute the magneto ignition leads for the test.   



At this point, since there is no compression in any cylinder, you can easily and with complete safety turn the propeller by hand OR by the starter if you wish.



If you rotate the propeller TWO turns in the normal direction of rotation, a spark should be observed at each sparkplug sometime during the two-turn rotation at the instant you hear the loud click of the impulse coupling snapping free.  In other words, a spark should occur once every other propeller rotation at the click.



Jerry King

_________________
Jerry King

EfraimOtero

Joined: 04 Nov 2020
Posts: 6
Location: Bogota Colombia South America

Posted: Tue Jan 12, 2021 11:34 am Post subject: Re: Magnetos

Bob, Jerry, Firstly may you have a happy and safe new year!



many thanks for your input! I will try Jerry's suggestion to test for sparks. I have to say I am not quite electrically savvy. I changed the spark plugs to brand new REM 40E and I will try the spark test.

I have also been looking for the proper P/N to replace the harness if necessary. Anyone know what this would be?

Again, thanks!



Ef

_________________
EfraimOtero
Fisher Celebrity EX N500BC
O200 COntinental

neal.george(at)gmail.com
Guest

Posted: Tue Jan 12, 2021 2:01 pm Post subject: Magnetos

Ef - Assuming your O-200 is fitted with Continental mags, the harness is P/N: 10-821471-17.

 Neal

=================On Jan 12, 2021, at 1:34 PM, EfraimOtero <efraim.otero(at)gmail.com (efraim.otero(at)gmail.com)> wrote:

--> AeroElectric-List message posted by: "EfraimOtero" <efraim.otero(at)gmail.com (efraim.otero(at)gmail.com)>Bob, Jerry, Firstly may you have a happy and safe new year!many thanks for your input! I will try Jerry's suggestion to test for sparks. I have to say I am not quite electrically savvy. I changed the spark plugs to brand new REM 40E and I will try the spark test.I have also been looking for the proper P/N to replace the harness if necessary. Anyone know what this would be?Again, thanks!Ef--------EfraimOteroFisher Celebrity EX N500BCO200 COntinental

EfraimOtero

Joined: 04 Nov 2020
Posts: 6
Location: Bogota Colombia South America

Posted: Tue Jan 12, 2021 2:25 pm Post subject: Re: Magnetos

Neal, thanks for the prompt response.

Mine are Bendix S4 LN -21 mags, P/N 10-51360-30. Are these the same as Continental? Gues not...?

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_________________
EfraimOtero
Fisher Celebrity EX N500BC
O200 COntinental

neal.george(at)gmail.com
Guest

Posted: Tue Jan 12, 2021 4:20 pm Post subject: Magnetos

Yes, they are the same.  Continental bought the Bendix ignition line about 35 years ago…



Neal



==================



On Jan 12, 2021, at 4:25 PM, EfraimOtero <efraim.otero(at)gmail.com> wrote:






Neal, thanks for the prompt response.

Mine are Bendix S4 LN -21 mags, P/N 10-51360-30. Are these the same as Continental? Gues not...? [Shocked]  [Embarassed]



--------

EfraimOtero

Fisher Celebrity EX N500BC

O200 COntinental

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