---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Tue 10/10/17: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:56 PM - CJ cough/miss fire/hesitation in flight (Harv) 2. 02:01 PM - Re: CJ cough/miss fire/hesitation in flight (Ernest Martinez) 3. 02:11 PM - Re: CJ cough/miss fire/hesitation in flight (A. Dennis Savarese) 4. 02:18 PM - Re: CJ cough/miss fire/hesitation in flight (Michael Wikstrom) 5. 02:21 PM - Re: CJ cough/miss fire/hesitation in flight (Gary Luther) 6. 03:26 PM - Re: CJ cough/miss fire/hesitation in flight (Bill Culberson) 7. 03:31 PM - Re: CJ cough/miss fire/hesitation in flight (George Coy) 8. 05:11 PM - Re: CJ cough/miss fire/hesitation in flight (Gary Gabbard) 9. 05:33 PM - Re: CJ cough/miss fire/hesitation in flight (Richard Kelley) 10. 09:56 PM - Re: CJ cough/miss fire/hesitation in flight (Royden Heays) 11. 10:02 PM - Re: CJ cough/miss fire/hesitation in flight (Ernest Martinez) 12. 11:17 PM - Re: CJ cough/miss fire/hesitation in flight (Nigel Willson) ________________________________ Message 1 _____________________________________ Time: 01:56:19 PM PST US Subject: Yak-List: CJ cough/miss fire/hesitation in flight From: "Harv" 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 ________________________________ Message 2 _____________________________________ Time: 02:01:06 PM PST US From: Ernest Martinez Subject: Re: Yak-List: 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 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 > > ________________________________ Message 3 _____________________________________ Time: 02:11:00 PM PST US From: "A. Dennis Savarese" Subject: Re: Yak-List: CJ cough/miss fire/hesitation in flight Bad coil.=C2- Typical problem after 20-40 minutes of flight.=C2- It tak es that long for the heat to permeate the coil.=C2- That's when the coil breaks down.=C2- Contact George Coy in Swanton, VT.=C2- I believe he ha s them.Dennis From: Harv To: yak-list@matronics.com Sent: Tuesday, October 10, 2017 4:57 PM Subject: Yak-List: 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 al l good. Take off fine but then once in the cruise after above amount of tim e engine seems to skip a beat and get rougher. Tried leaning, richening, ca rb heat, fuel primer locked, hotter and cooler cyl head temps all with no d ifference 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 bot h be changed as a precaution for age)? I've asked Doug but he hasn't any st ock. Are the old ones re build able? Thanks in advance. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473443#473443 S - WIKI - - =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. ________________________________ Message 4 _____________________________________ Time: 02:18:42 PM PST US From: Michael Wikstrom Subject: Re: Yak-List: CJ cough/miss fire/hesitation in flight I agree, bad coil. Had similar problem, bought a coil from Richard Goode, i nstalled it and problem fixed. Cheers Michael Wikstr=C3=B6m [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@mssfrance.com Web: www.mssfrance.com VAT No: FR69347398729 > On 10 Oct 2017, at 22:59, Ernest Martinez wrote: > > Probably a bad coil in the mag. > > Ernie > >> On Tue, Oct 10, 2017 at 4:55 PM, Harv 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 a ll good. Take off fine but then once in the cruise after above amount of tim e engine seems to skip a beat and get rougher. Tried leaning, richening, car b heat, fuel primer locked, hotter and cooler cyl head temps all with no dif ference 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 a s yet. >> >> Any ideas sought. >> >> If it's indeed a mag coil then anyone got a source for new ones (should b oth be changed as a precaution for age)? I've asked Doug but he hasn't any s tock. >> >> >> >> 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/Navig ator?Yak-List >> ========================= >> FORUMS - >> eferrer" target="_blank">http://forums.matronics.com >> ========================= >> WIKI - >> errer" target="_blank">http://wiki.matronics.com >> ========================= >> b Site - >> -Matt Dralle, List Admin. >> rel="noreferrer" target="_blank">http://www.matronics.com/contributio n >> ========================= >> >> >> > ________________________________ Message 5 _____________________________________ Time: 02:21:47 PM PST US From: Gary Luther Subject: Re: Yak-List: CJ cough/miss fire/hesitation in flight George Coy has them On Tue, Oct 10, 2017 at 3:55 PM, Harv 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 > > ________________________________ Message 6 _____________________________________ Time: 03:26:53 PM PST US From: Bill Culberson Subject: Re: Yak-List: 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 > On Oct 10, 2017, at 3:55 PM, Harv 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 > > > > > > > > > ________________________________ Message 7 _____________________________________ Time: 03:31:04 PM PST US From: George Coy Subject: Re: Yak-List: CJ cough/miss fire/hesitation in flight I think I have at least one in stock. I can order more. They are new product ion. Contact off list. George coy Sent from my iPad > On Oct 10, 2017, at 5:09 PM, A. Dennis Savarese wrote: > > Bad coil. Typical problem after 20-40 minutes of flight. It takes that l ong for the heat to permeate the coil. That's when the coil breaks down. C ontact George Coy in Swanton, VT. I believe he has them. > Dennis > > > From: Harv > To: yak-list@matronics.com > Sent: Tuesday, October 10, 2017 4:57 PM > Subject: Yak-List: 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 a ll good. Take off fine but then once in the cruise after above amount of tim e engine seems to skip a beat and get rougher. Tried leaning, richening, car b heat, fuel primer locked, hotter and cooler cyl head temps all with no dif ference 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 a s yet. > > Any ideas sought. > > If it's indeed a mag coil then anyone got a source for new ones (should bo th be changed as a precaution for age)? I've asked Doug but he hasn't any st ock. > > > > 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/" t arget="_blank">http://wiki.matronics.com > ; -Matt Draltp://www.matronics.com/contribution" target= "_blank">http://www.matronics= > > > > > ________________________________ Message 8 _____________________________________ Time: 05:11:47 PM PST US From: Gary Gabbard Subject: Re: Yak-List: 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 > On Oct 10, 2017, at 15:25, Bill Culberson 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 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 >> >> >> >> >> >> >> >> >> > > > > ________________________________ Message 9 _____________________________________ Time: 05:33:03 PM PST US From: Richard Kelley Subject: Re: Yak-List: 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 > On Oct 10, 2017, at 5:25 PM, Bill Culberson 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 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 >> >> >> >> >> >> >> >> >> > > > > ________________________________ Message 10 ____________________________________ Time: 09:56:22 PM PST US From: "Royden Heays" Subject: RE: Yak-List: 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 -----Original Message----- From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Harv Sent: Tuesday, October 10, 2017 1:56 PM Subject: Yak-List: 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. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473443#473443 ________________________________ Message 11 ____________________________________ Time: 10:02:48 PM PST US From: Ernest Martinez Subject: Re: Yak-List: 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 wrote: > > 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 > > > -----Original Message----- > From: owner-yak-list-server@matronics.com > [mailto:owner-yak-list-server@matronics.com] On Behalf Of Harv > Sent: Tuesday, October 10, 2017 1:56 PM > To: yak-list@matronics.com > Subject: Yak-List: 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. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=473443#473443 > > ________________________________ Message 12 ____________________________________ Time: 11:17:53 PM PST US From: Nigel Willson Subject: Re: Yak-List: CJ cough/miss fire/hesitation in flight Agreed. Same on a 52 from first hand experience. Bad coil affects both mags s trangely. 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 wrote: > > 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 wrote: >> >> 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 int o >> the problem? Intermittent Mag problems and spark plug problems are worse a t >> 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 a nd >> 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 a s >> 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 i t >> turned out to be the pressure carb. They are supposed to be overhauled ev ery >> six years when all rubber parts are replaced. I had a spare carb that ha d >> been recently overhauled which I canalized off a second old engine. Swapp ed >> it out and that got rid of the missing beat. >> >> On another more recent occasion, had a slightly rough running engine abou t 2 >> hours into a flight at 3000 ft and at 70% RPM . I thought it might be fue l >> 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 fro m >> 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 w eek >> 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 >> >> >> >> -----Original Message----- >> From: owner-yak-list-server@matronics.com >> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Harv >> Sent: Tuesday, October 10, 2017 1:56 PM >> To: yak-list@matronics.com >> Subject: Yak-List: 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 a ll >> good. Take off fine but then once in the cruise after above amount of tim e >> engine seems to skip a beat and get rougher. Tried leaning, richening, ca rb >> 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 a s >> yet. >> >> Any ideas sought. >> >> If it's indeed a mag coil then anyone got a source for new ones (should b oth >> 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/Navig ator?Yak-List >> ========== >> FORUMS - >> eferrer" target="_blank">http://forums.matronics.com >> ========== >> WIKI - >> errer" target="_blank">http://wiki.matronics.com >> ========== >> b Site - >> -Matt Dralle, List Admin. >> rel="noreferrer" target="_blank">http://www.matronics.com/contributio n >> ========== >> >> >> ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.