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CJ cough/miss fire/hesitation in flight

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Harv

Joined: 01 Jul 2010
Posts: 170

Posted: Tue Oct 10, 2017 12:55 pm Post subject: CJ cough/miss fire/hesitation in flight

Gents



Advice sought as I have a slight misfire in flight after 25mins so.



Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.



Can this be isolated on the ground via prolonged warm up? I've not tried as yet.



Any ideas sought.



If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.



Are the old ones re build able?



Thanks in advance.

Ernie

Joined: 11 Jan 2006
Posts: 513

Posted: Tue Oct 10, 2017 1:01 pm Post subject: CJ cough/miss fire/hesitation in flight

Probably a bad coil in the mag.



Ernie

On Tue, Oct 10, 2017 at 4:55 PM, Harv <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "Harv" <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>

 

 Gents

 

 Advice sought as I have a slight misfire in flight after 25mins so.

 

 Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

 

 Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

 

 Any ideas sought.

 

 If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

 

 

 

 Are the old ones re build able?

 

 Thanks in advance.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=473443#473443

 

 

 

 

 

 

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dsavarese0812(at)bellsout
Guest

Posted: Tue Oct 10, 2017 1:10 pm Post subject: CJ cough/miss fire/hesitation in flight

Bad coil.  Typical problem after 20-40 minutes of flight.  It takes that long for the heat to permeate the coil.  That's when the coil breaks down.  Contact George Coy in Swanton, VT.  I believe he has them.

Dennis

       From: Harv <martin.harvey(at)kbr.com>

 To: yak-list(at)matronics.com 

 Sent: Tuesday, October 10, 2017 4:57 PM

 Subject: Yak-List: CJ cough/miss fire/hesitation in flight

--> Yak-List message posted by: "Harv" <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>

Gents

Advice sought as I have a slight misfire in flight after 25mins so.

Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

Any ideas sought.

If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

Are the old ones re build able?

Thanks in advance.

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=473443#473443

http://www.matronics.com/Np;              - MATRONICS WEB FORUMS -

<;  --> http:/nbsp;             - NEW MATRONICS LIST WIKI -matronics.com/" target="_blank">http://wiki.matronics.com

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michael(at)wikstrom.cc
Guest

Posted: Tue Oct 10, 2017 1:18 pm Post subject: CJ cough/miss fire/hesitation in flight

I agree, bad coil.  Had similar problem, bought a coil from Richard Goode, installed it and problem fixed.



Cheers



Michael WikstrÃ¶m [iPhone]

Marine Satellite Systems

Les Espaces de Sophia

80 Route des Lucioles

06560 Valbonne

France

 

Tel:     +33 493 958 093

Gsm: +33 607 44 40 11

 Fax:    +33 493 958 042

Email: michael(at)mssfrance.com (michael(at)mssfrance.com)

Web: www.mssfrance.com

VAT No: FR69347398729





On 10 Oct 2017, at 22:59, Ernest Martinez <erniel29(at)gmail.com (erniel29(at)gmail.com)> wrote:

 	  Quote: 	
		  Probably a bad coil in the mag.



Ernie

On Tue, Oct 10, 2017 at 4:55 PM, Harv <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "Harv" <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>

 

 Gents

 

 Advice sought as I have a slight misfire in flight after 25mins so.

 

 Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

 

 Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

 

 Any ideas sought.

 

 If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

 

 

 

 Are the old ones re build able?

 

 Thanks in advance.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=473443#473443

 

 

 

 

 

 

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 eferrer" target="_blank">http://forums.matronics.com

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GL

Joined: 26 Apr 2016
Posts: 2
Location: Franklin, Tn

Posted: Tue Oct 10, 2017 1:21 pm Post subject: CJ cough/miss fire/hesitation in flight

George Coy has them



On Tue, Oct 10, 2017 at 3:55 PM, Harv <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "Harv" <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>

 

 Gents

 

 Advice sought as I have a slight misfire in flight after 25mins so.

 

 Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

 

 Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

 

 Any ideas sought.

 

 If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

 

 

 

 Are the old ones re build able?

 

 Thanks in advance.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=473443#473443

 

 

 

 

 

 

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

 List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List

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

  FORUMS -

 eferrer" target="_blank">http://forums.matronics.com

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

 WIKI -

 errer" target="_blank">http://wiki.matronics.com

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 b Site -

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 rel="noreferrer" target="_blank">http://www.matronics.com/contribution

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migfighter42(at)gmail.com
Guest

Posted: Tue Oct 10, 2017 2:26 pm Post subject: CJ cough/miss fire/hesitation in flight

It does indeed sound like a coil. I would think M-14P has them.



Bill

Red Star Aero Services



Sent from my iPhone



 	  Quote: 	
		   On Oct 10, 2017, at 3:55 PM, Harv <martin.harvey(at)kbr.com> wrote:

 

 

 

 Gents

 

 Advice sought as I have a slight misfire in flight after 25mins so.

 

 Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

 

 Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

 

 Any ideas sought.

 

 If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

 

 

 

 Are the old ones re build able?

 

 Thanks in advance.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=473443#473443

GeorgeCoy

Joined: 02 Dec 2010
Posts: 308

Posted: Tue Oct 10, 2017 2:31 pm Post subject: CJ cough/miss fire/hesitation in flight

I think I have at least one in stock. I can order more. They are new production.  Contact off list.

George coy



Sent from my iPad



On Oct 10, 2017, at 5:09 PM, A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:

 	  Quote: 	
		  Bad coil.  Typical problem after 20-40 minutes of flight.  It takes that long for the heat to permeate the coil.  That's when the coil breaks down.  Contact George Coy in Swanton, VT.  I believe he has them.

Dennis



       From: Harv <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>

 To: yak-list(at)matronics.com (yak-list(at)matronics.com) 

 Sent: Tuesday, October 10, 2017 4:57 PM

 Subject: Yak-List: CJ cough/miss fire/hesitation in flight

  

 

--> Yak-List message posted by: "Harv" <martin.harvey(at)kbr.com (martin.harvey(at)kbr.com)>



Gents



Advice sought as I have a slight misfire in flight after 25mins so.



Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.



Can this be isolated on the ground via prolonged warm up? I've not tried as yet.



Any ideas sought.



If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.



Are the old ones re build able?



Thanks in advance.



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=473443#473443





http://www.matronics.com/Np;              - MATRONICS WEB FORUMS -

<;  --> http:/nbsp;             - NEW MATRONICS LIST WIKI -matronics.com/" target="_blank">http://wiki.matronics.com



;                   -Matt Draltp://www.matronics.com/contribution" target="_blank">http://www.matronics==

jackpot

Joined: 13 Jul 2010
Posts: 65
Location: Las Vegas, Nevada

Posted: Tue Oct 10, 2017 4:11 pm Post subject: CJ cough/miss fire/hesitation in flight

Check the gap on the points. Been there done that.  Fixed the problem. This may not be your problem.  Remember the gap is in millimeters.   Gary. LAS. CJ-22YK



Sent from my iPhone



 	  Quote: 	
		   On Oct 10, 2017, at 15:25, Bill Culberson <migfighter42(at)gmail.com> wrote:

 

 

 

 It does indeed sound like a coil. I would think M-14P has them.

 

 Bill

 Red Star Aero Services

 

 Sent from my iPhone

 

> On Oct 10, 2017, at 3:55 PM, Harv <martin.harvey(at)kbr.com> wrote:

> 

> 

> 

> Gents

> 

> Advice sought as I have a slight misfire in flight after 25mins so.

> 

> Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

> 

> Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

> 

> Any ideas sought.

> 

> If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

> 

> 

> 

> Are the old ones re build able?

> 

> Thanks in advance.

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=473443#473443

> 

> 

> 

> 

> 

> 

> 

> 

>

rickkelleyfly(at)gmail.co
Guest

Posted: Tue Oct 10, 2017 4:33 pm Post subject: CJ cough/miss fire/hesitation in flight

Yes could be a coil most like. My was the oil wick had to much oil in it and keep filling the points with oil. Been fine for the last 100 hrs. 

Thug



Sent from my iPhone



 	  Quote: 	
		   On Oct 10, 2017, at 5:25 PM, Bill Culberson <migfighter42(at)gmail.com> wrote:

 

 

 

 It does indeed sound like a coil. I would think M-14P has them.

 

 Bill

 Red Star Aero Services

 

 Sent from my iPhone

 

> On Oct 10, 2017, at 3:55 PM, Harv <martin.harvey(at)kbr.com> wrote:

> 

> 

> 

> Gents

> 

> Advice sought as I have a slight misfire in flight after 25mins so.

> 

> Always seems fine on the ground run up from cold, no mag drop, t's & p's all good. Take off fine but then once in the cruise after above amount of time engine seems to skip a beat and get rougher. Tried leaning, richening, carb heat, fuel primer locked, hotter and cooler cyl head temps all with no difference and my gut feeling is a mag is going bad.

> 

> Can this be isolated on the ground via prolonged warm up? I've not tried as yet.

> 

> Any ideas sought.

> 

> If it's indeed a mag coil then anyone got a source for new ones (should both be changed as a precaution for age)? I've asked Doug but he hasn't any stock.

> 

> 

> 

> Are the old ones re build able?

> 

> Thanks in advance.

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=473443#473443

> 

> 

> 

> 

> 

> 

> 

> 

>

heaysr(at)telus.net
Guest

Posted: Tue Oct 10, 2017 8:56 pm Post subject: CJ cough/miss fire/hesitation in flight

Hello Harv,



I have had the same problem on the M14P in a Yak 55M. Not sure if you are

talking about a Housai. Was your flight at high altitude when you ran into

the problem? Intermittent Mag problems and spark plug problems are worse at

high altitude.



In flight, when the problem occurs, try turning one mag off and see if

engine runs smoothly. Then then switch that one on and the other mag off and

check for smooth running again. If it runs rough or with an occasional

skipping a beat on each mag one by one it's unlikely to be a mag problem as

it's unlikely both mag coils would start to fail simultaneously.



In my case of missing a beat, it was on a freshly overhauled engine and it

turned out to be the pressure carb. They are supposed to be overhauled every

six years when all rubber parts are replaced.  I had a spare carb that had

been recently overhauled which I canalized off a second old engine. Swapped

it out and that got rid of the missing beat. 



On another more recent occasion, had a slightly rough running engine about 2

hours into a flight at 3000 ft and at 70% RPM . I thought it might be fuel

hanging up in a slightly clogged air vent, but increasing power to 80% to

85% to 90% didn't make it worse or better.  The roughness was obvious from

vibration and sound and also from a slightly wavering tach needle.  Even

though mags were 3% drop on each at run-up - it happened again the next week

about 1 hour into a flight at 2500 ft. Not nice - it was over water. That

was followed immediately by annual inspection. Plugs were rather sooty -

maybe carb is a bit rich. Nothing else untoward was found.  Plugs were

cleaned  - haven't has a problem since , albeit, have only done one short

flight and two longer flights of around 1 hour each. So the jury is still

out on that problem, at least until I do a longer flight.



Best regards



Royden  



--

Ernie

Joined: 11 Jan 2006
Posts: 513

Posted: Tue Oct 10, 2017 9:02 pm Post subject: CJ cough/miss fire/hesitation in flight

Nope. One bad coil will affect both sides. Must be a design flaw but it is a well known fact.



On Wed, Oct 11, 2017 at 12:58 AM Royden Heays <heaysr(at)telus.net (heaysr(at)telus.net)> wrote:



[quote]--> Yak-List message posted by: "Royden Heays" <heaysr(at)telus.net (heaysr(at)telus.net)>

 

 Hello Harv,

 

 I have had the same problem on the M14P in a Yak 55M. Not sure if you are

 talking about a Housai. Was your flight at high altitude when you ran into

 the problem? Intermittent Mag problems and spark plug problems are worse at

 high altitude.

 

 In flight, when the problem occurs, try turning one mag off and see if

 engine runs smoothly. Then then switch that one on and the other mag off and

 check for smooth running again. If it runs rough or with an occasional

 skipping a beat on each mag one by one it's unlikely to be a mag problem as

 it's unlikely both mag coils would start to fail simultaneously.

 

 In my case of missing a beat, it was on a freshly overhauled engine and it

 turned out to be the pressure carb. They are supposed to be overhauled every

 six years when all rubber parts are replaced.Â  I had a spare carb that had

 been recently overhauled which I canalized off a second old engine. Swapped

 it out and that got rid of the missing beat.

 

 On another more recent occasion, had a slightly rough running engine about 2

 hours into a flight at 3000 ft and at 70% RPM . I thought it might be fuel

 hanging up in a slightly clogged air vent, but increasing power to 80% to

 85% to 90% didn't make it worse or better.Â  The roughness was obvious from

 vibration and sound and also from a slightly wavering tach needle.Â  Even

 though mags were 3% drop on each at run-up - it happened again the next week

 about 1 hour into a flight at 2500 ft. Not nice - it was over water. That

 was followed immediately by annual inspection. Plugs were rather sooty -

 maybe carb is a bit rich. Nothing else untoward was found.Â  Plugs were

 cleanedÂ  - haven't has a problem since , albeit, have only done one short

 flight and two longer flights of around 1 hour each. So the jury is still

 out on that problem, at least until I do a longer flight.

 

 Best regards

 

 Royden

 

 

 

 --

nigel.willson(at)yakdispl
Guest

Posted: Tue Oct 10, 2017 10:17 pm Post subject: CJ cough/miss fire/hesitation in flight

Agreed. Same on a 52 from first hand experience. Bad coil affects both mags strangely.



Regards,



Nigel Willson

Flying Instructor & Examiner | Airshow Organiser | Display Pilot

Tel. 07809 116676

www.yakdisplay.com

Sent from my iPad

On 11 Oct 2017, at 06:01, Ernest Martinez <erniel29(at)gmail.com (erniel29(at)gmail.com)> wrote:

[quote]Nope. One bad coil will affect both sides. Must be a design flaw but it is a well known fact.



On Wed, Oct 11, 2017 at 12:58 AM Royden Heays <heaysr(at)telus.net (heaysr(at)telus.net)> wrote:



[quote]--> Yak-List message posted by: "Royden Heays" <heaysr(at)telus.net (heaysr(at)telus.net)>

 

 Hello Harv,

 

 I have had the same problem on the M14P in a Yak 55M. Not sure if you are

 talking about a Housai. Was your flight at high altitude when you ran into

 the problem? Intermittent Mag problems and spark plug problems are worse at

 high altitude.

 

 In flight, when the problem occurs, try turning one mag off and see if

 engine runs smoothly. Then then switch that one on and the other mag off and

 check for smooth running again. If it runs rough or with an occasional

 skipping a beat on each mag one by one it's unlikely to be a mag problem as

 it's unlikely both mag coils would start to fail simultaneously.

 

 In my case of missing a beat, it was on a freshly overhauled engine and it

 turned out to be the pressure carb. They are supposed to be overhauled every

 six years when all rubber parts are replaced.  I had a spare carb that had

 been recently overhauled which I canalized off a second old engine. Swapped

 it out and that got rid of the missing beat.

 

 On another more recent occasion, had a slightly rough running engine about 2

 hours into a flight at 3000 ft and at 70% RPM . I thought it might be fuel

 hanging up in a slightly clogged air vent, but increasing power to 80% to

 85% to 90% didn't make it worse or better.  The roughness was obvious from

 vibration and sound and also from a slightly wavering tach needle.  Even

 though mags were 3% drop on each at run-up - it happened again the next week

 about 1 hour into a flight at 2500 ft. Not nice - it was over water. That

 was followed immediately by annual inspection. Plugs were rather sooty -

 maybe carb is a bit rich. Nothing else untoward was found.  Plugs were

 cleaned  - haven't has a problem since , albeit, have only done one short

 flight and two longer flights of around 1 hour each. So the jury is still

 out on that problem, at least until I do a longer flight.

 

 Best regards

 

 Royden

 

 

 

 --

Harv

Joined: 01 Jul 2010
Posts: 170

Posted: Wed Oct 11, 2017 12:14 am Post subject: Re: CJ cough/miss fire/hesitation in flight

Thanks for the replies.



This is a Housai and we are fresh out of annual, points are cleaned and gapped, timing set, compressions all good, one new cigar cartridge.



I've had this once before and don't associate it to above works (this is why I think it could be a mag coil) but will check through the items raised.



It's not a particularly nice feeling when it skips for that heart beat but maybe I'll have to fly her again to pinpoint which mag is giving out. 



I'll try an increase temp run up first and see if she'll misbehave on the ground (that would be nice)



Will update with findings.



Cheers

Harv

nigel.willson(at)yakdispl
Guest

Posted: Wed Oct 11, 2017 12:49 am Post subject: CJ cough/miss fire/hesitation in flight

It's not worth bothering trying to figure out which mag.



Also beware of "old" new spares. The coils deteriorate on the shelf as well

as "in life".



I replaced mine with brand new in all respects from M14P.

Regards, 

Nigel Willson

Flying Instructor & Examiner | Airshow Organiser | Display Pilot



 



Mobile:

+44 (0)7809 116676

Email:

nigel.willson(at)yakdisplay.com

Web:

http://easyppl.com 

http://greatbritishairshows.com

http://yakdisplay.com





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