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CJ6 Hot Starts

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Okanogan Lew

Joined: 22 Jul 2010
Posts: 45

Posted: Mon Jul 26, 2010 10:32 am Post subject: CJ6 Hot Starts

Hey guys, I got one for you.  I flew into Fairchild AFB for a show & parked the CJ.  The next day we were to fly in the show & start up time was noon.  By then it was about 90 degrees & I preformed my standard start-up routine, which is 5 primes with a pull of the blade between each.  I hit the start & the engine turned over,  but would not start.  It didn't even fire.  I gave it 3 more primes, but still nothing.  I then gave it about 5 primes & still nothing.  By then, I was very low on air & gave up.  The next morning about 0700 I tried it again with my usual start-up routine & the blade turned about a half & it fired off.  I ran it for about 15 minutes & shut it down.  We were again scheduled to fly at noon & by then it was in the mid 90's.  I did my usual start-up & again it would turn over, but wouldn't even fire.  I primed the hell out of it & still nothing.  Finally gave up again.  This morning, it started with the usual start up routine.  Go Figure!!  A couple of points.  I had 1/2 car gas & 1/2 av gas in the tanks.  The right side of the plane (primer side)  was facing the sun.  Do you think the heat cased a vapor lock in the primer tube & was blocking the fuel flow?  Any other thoughts?  I have the 285 HP engine & it ran fine for the hour trip home.  Thanks in advance for an info.

mark.bitterlich(at)navy.m
Guest

Posted: Mon Jul 26, 2010 1:51 pm Post subject: CJ6 Hot Starts

I personally think this has something to do with the "shower of sparks"

(Booster Coil... Whatever) system used in these aircraft.  I had a very

bad problem with this exact same thing in my YAK-50, and it still is not

totally corrected, but since I use Dennis's high performance wire and

plugs, I was able to correct a lot of this by using a plug gap of .020

versus .032, or .035   However, the engine would always start when cold,

even when using a .035 plug gap and it always RAN well once started even

with that wide plug gap.  This tends to infer that for some reason the

starting system is not producing enough energy to fire properly with a

hot engine and a wide plug gap.  I really am not sure how much this has

to do with fuel.  I was running 100% 100 Low Lead at the time.   The

engine simply would not start when hot and did EXACTLY what yours did.

Outside temperature on the days this happened were also in the 90's.  So

while fuel MIGHT have been involved, it sure did not have anything to do

with MO-GAS being used.  



I worked on this problem a long time.  I replaced the Shower of Sparks

vibrator coil with one from another YAK-50.  However, it was NOT a new

one.  Never-the-less, a working one.  It did not help.  I replaced the

high tension wire going from the coil to the mag.  No help.  I then

devised a way to make darn sure that the wire running from the coil to

the mag was making good contact inside the mag cap (where normally the

wire is penetrated by a sharp screw in pin.  No help.  I replaced the

mag rotor.  No help.  I then replaced the mag cap.  No help.   I then

put in new spark plugs gapped to .020   Problem went away... Mostly.

But it still rears it's ugly head now and again on a very hot start.  



A gent from Australia (sorry I forget your name) mentioned that there is

an adjustment of the buzzer points that are internal to the shower of

sparks coil, and he is absolutely correct.  I took a few apart and saw

that adjustment but did not toy with it, because I was reluctant to

change it not knowing what the exact gap is supposed to be.  Since the

Shower of Sparks coils are identical in the YAK-50 and the CJ-6A models,

I wonder if Doug or anyone else has a "Task Card" that specifies what

that gap is supposed to be.  Like the Australian Gent, I have a strong

feeling that this gap will make a HUGE difference in the voltage output.

Misadjustment could easily result in not enough energy to fire a really

hot engine, and I have suspected this might have been my problem all

along.  I just am not sure how to test this though.  Looking at the

output of a coil like that is not really simplistic, but it might be

simply a matter of trying what the other gent did, and just move it one

or two clicks and see what happens.



In any case, I don't have a definitive answer, and the matter is worth

discussing.  



Mark Bitterlich

   



--

dsavarese0812(at)bellsout
Guest

Posted: Mon Jul 26, 2010 2:05 pm Post subject: CJ6 Hot Starts

Take a look at the points in the "shower of sparks"  unit.  I would venture a guess they are pitted.  If so, burnish the  points with a fine point file and test again.  I do not know the correct  gap, but Mark is 100% right, as usual.  The gap will make a huge difference  in the spark.  With the "mounding" of the points, the gap is reduced and  the output of the unit is also reduced.  Clean up the points first.   Then for experimentation, adjust the gap and watch the spark "jump" from the  wire to ground.  REAL easy to do on the CJ by simply removing the  cover.  The wider the point gap, the bigger the spark jump....to a  point.  Get them too wide and nothing will happen.  I adjusted mine at  one time after burnishing the points and called the adjustment the "that looks  good adjustment"  or as we say in Alabama, 'bout right!

 Dennis

 [quote]   ---

okanoganlew(at)gmail.com
Guest

Posted: Mon Jul 26, 2010 2:46 pm Post subject: CJ6 Hot Starts

Mark, where is the shower of sparks unit located?  I assume it's close to the mags? I have 5 chinese manuals, but none of them show it.

  

 Paul

 On Mon, Jul 26, 2010 at 2:50 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:

  [quote]--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>

 

I personally think this has something to do with the "shower of sparks"

(Booster Coil... Whatever) system used in these aircraft.  I had a very

bad problem with this exact same thing in my YAK-50, and it still is not

 totally corrected, but since I use Dennis's high performance wire and

plugs, I was able to correct a lot of this by using a plug gap of .020

versus .032, or .035   However, the engine would always start when cold,

 even when using a .035 plug gap and it always RAN well once started even

with that wide plug gap.  This tends to infer that for some reason the

starting system is not producing enough energy to fire properly with a

 hot engine and a wide plug gap.  I really am not sure how much this has

to do with fuel.  I was running 100% 100 Low Lead at the time.   The

engine simply would not start when hot and did EXACTLY what yours did.

 Outside temperature on the days this happened were also in the 90's.  So

while fuel MIGHT have been involved, it sure did not have anything to do

with MO-GAS being used.



I worked on this problem a long time.  I replaced the Shower of Sparks

 vibrator coil with one from another YAK-50.  However, it was NOT a new

one.  Never-the-less, a working one.  It did not help.  I replaced the

high tension wire going from the coil to the mag.  No help.  I then

devised a way to make darn sure that the wire running from the coil to

 the mag was making good contact inside the mag cap (where normally the

wire is penetrated by a sharp screw in pin.  No help.  I replaced the

mag rotor.  No help.  I then replaced the mag cap.  No help.   I then

put in new spark plugs gapped to .020   Problem went away... Mostly.

 But it still rears it's ugly head now and again on a very hot start.



A gent from Australia (sorry I forget your name) mentioned that there is

an adjustment of the buzzer points that are internal to the shower of

 sparks coil, and he is absolutely correct.  I took a few apart and saw

that adjustment but did not toy with it, because I was reluctant to

change it not knowing what the exact gap is supposed to be.  Since the

Shower of Sparks coils are identical in the YAK-50 and the CJ-6A models,

 I wonder if Doug or anyone else has a "Task Card" that specifies what

that gap is supposed to be.  Like the Australian Gent, I have a strong

feeling that this gap will make a HUGE difference in the voltage output.

 Misadjustment could easily result in not enough energy to fire a really

hot engine, and I have suspected this might have been my problem all

along.  I just am not sure how to test this though.  Looking at the

output of a coil like that is not really simplistic, but it might be

 simply a matter of trying what the other gent did, and just move it one

or two clicks and see what happens.



In any case, I don't have a definitive answer, and the matter is worth

discussing.



 Mark Bitterlich

  

 



--

dougsappllc(at)gmail.com
Guest

Posted: Mon Jul 26, 2010 2:58 pm Post subject: CJ6 Hot Starts

Paul,

Normally on the left hand top motor mount leg, has a shielded plug wire lead coming out of it.  Have also seen them mounted on the fire wall, but always on the left hand side.

Doug

 

On Mon, Jul 26, 2010 at 3:45 PM, Paul Lewis <okanoganlew(at)gmail.com (okanoganlew(at)gmail.com)> wrote:

[quote] Mark, where is the shower of sparks unit located?  I assume it's close to the mags? I have 5 chinese manuals, but none of them show it.

  

 Paul

 On Mon, Jul 26, 2010 at 2:50 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)> wrote:

   [quote]--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" <mark.bitterlich(at)navy.mil (mark.bitterlich(at)navy.mil)>

  

I personally think this has something to do with the "shower of sparks"

(Booster Coil... Whatever) system used in these aircraft.  I had a very

bad problem with this exact same thing in my YAK-50, and it still is not

  totally corrected, but since I use Dennis's high performance wire and

plugs, I was able to correct a lot of this by using a plug gap of .020

versus .032, or .035   However, the engine would always start when cold,

  even when using a .035 plug gap and it always RAN well once started even

with that wide plug gap.  This tends to infer that for some reason the

starting system is not producing enough energy to fire properly with a

  hot engine and a wide plug gap.  I really am not sure how much this has

to do with fuel.  I was running 100% 100 Low Lead at the time.   The

engine simply would not start when hot and did EXACTLY what yours did.

  Outside temperature on the days this happened were also in the 90's.  So

while fuel MIGHT have been involved, it sure did not have anything to do

with MO-GAS being used.



I worked on this problem a long time.  I replaced the Shower of Sparks

  vibrator coil with one from another YAK-50.  However, it was NOT a new

one.  Never-the-less, a working one.  It did not help.  I replaced the

high tension wire going from the coil to the mag.  No help.  I then

devised a way to make darn sure that the wire running from the coil to

  the mag was making good contact inside the mag cap (where normally the

wire is penetrated by a sharp screw in pin.  No help.  I replaced the

mag rotor.  No help.  I then replaced the mag cap.  No help.   I then

 put in new spark plugs gapped to .020   Problem went away... Mostly.

 But it still rears it's ugly head now and again on a very hot start.



A gent from Australia (sorry I forget your name) mentioned that there is

an adjustment of the buzzer points that are internal to the shower of

  sparks coil, and he is absolutely correct.  I took a few apart and saw

that adjustment but did not toy with it, because I was reluctant to

change it not knowing what the exact gap is supposed to be.  Since the

Shower of Sparks coils are identical in the YAK-50 and the CJ-6A models,

  I wonder if Doug or anyone else has a "Task Card" that specifies what

that gap is supposed to be.  Like the Australian Gent, I have a strong

feeling that this gap will make a HUGE difference in the voltage output.

  Misadjustment could easily result in not enough energy to fire a really

hot engine, and I have suspected this might have been my problem all

along.  I just am not sure how to test this though.  Looking at the

output of a coil like that is not really simplistic, but it might be

  simply a matter of trying what the other gent did, and just move it one

or two clicks and see what happens.



In any case, I don't have a definitive answer, and the matter is worth

discussing.



  Mark Bitterlich

  

 



--

dsavarese0812(at)bellsout
Guest

Posted: Mon Jul 26, 2010 3:44 pm Post subject: CJ6 Hot Starts

It is mounted on the upper engine mount on the left side (from  the cockpit).  There is a shielded wire coming from the unit to the front  cover plate of the left magneto.  Look at the right mag and you will see  there is no shielded wire going to the front cover plate.

 Dennis 

 [quote]   ---

viperdoc(at)mindspring.co
Guest

Posted: Mon Jul 26, 2010 4:49 pm Post subject: CJ6 Hot Starts

Okanogan,

Don't know what the CJ procedure for starting the engine when it is hot but

the YAK calls for a couple of strokes of prime to start when the temp is

over 90 degrees (35 -37 C). I do not have my 42 manual close buy but

remember it called for less prime than the 6 in winter. I personally prime

first then pull 4 blades stopping on a compression stroke (I assume that

with increase in resistance to advance the blade). Is it possible that you

have over primed?

Next time this happens open your intake drain if you have one in place to

see how much fuel drains out. 

We had (have) temps in Alabama now constantly in the high 90's F. and I have

not had an issue starting the 52. I had a different issue with the 50

starting but it had nothing to do with fuel vapor pressure or the electrical

system. It has more to do with leaking air around the base of a couple of my

air injectors. At least I think it was that so far.

I am running 100 LL too.

Doc



--

Noplugs

Joined: 27 Aug 2009
Posts: 35
Location: Houston, TX

Posted: Mon Jul 26, 2010 5:28 pm Post subject: Re: CJ6 Hot Starts

Paul 

Look in your manual Figure 11-12

cj.jpg

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151.15 KB

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wlannon(at)persona.ca
Guest

Posted: Mon Jul 26, 2010 7:03 pm Post subject: CJ6 Hot Starts

Your problem is simple. It is pretty severe over priming.

You are trying to fire up a air/fuel mixture with a ratio of maybe 3:1 (?) 

instead of about 14:1.  You are also washing the cylinder walls of oil which 

is already thinned out by the high temperature and increasing the 

possibility of hydraulic lock with excess fuel.



In the conditions you describe I use 1 or 2 shots after filling the primer 

for the Huosai and the M14P.  Works every time.  For the R1340 I use 1/2 

shot after filling the primer (large barrel type).



In addition I never pull the prop through while priming.  I put that in the 

same category as Russian roulette.  If you have a failed mag. switch, a 

disconnected or a broken "P"

lead you have a live mag. and are flirting with disaster.



Walt



---

okanoganlew(at)gmail.com
Guest

Posted: Mon Jul 26, 2010 7:30 pm Post subject: CJ6 Hot Starts

Thanks Walt, I posed the overpriming question to the Yak List a while back & was told that the priming mixture went into the super charger & wouldn't wash down the cyclinders.  Was that bad info?

  

 Paul

 On Mon, Jul 26, 2010 at 8:02 PM, Walter Lannon <wlannon(at)persona.ca (wlannon(at)persona.ca)> wrote:

 [quote]--> Yak-List message posted by: Walter Lannon <wlannon(at)persona.ca (wlannon(at)persona.ca)>

 

Your problem is simple. It is pretty severe over priming.

You are trying to fire up a air/fuel mixture with a ratio of maybe 3:1 (?) instead of about 14:1.  You are also washing the cylinder walls of oil which is already thinned out by the high temperature and increasing the possibility of hydraulic lock with excess fuel.

 

In the conditions you describe I use 1 or 2 shots after filling the primer for the Huosai and the M14P.  Works every time.  For the R1340 I use 1/2 shot after filling the primer (large barrel type).



In addition I never pull the prop through while priming.  I put that in the same category as Russian roulette.  If you have a failed mag. switch, a disconnected or a broken "P"

 lead you have a live mag. and are flirting with disaster.



Walt



---

wlannon(at)persona.ca
Guest

Posted: Mon Jul 26, 2010 7:33 pm Post subject: CJ6 Hot Starts

Paul;

 The reason for that is simply that it is not a  'shower of sparks" system. 

 The subject has been discussed ad infinitum on this  list but of course makes no difference. 

 In our lexicon it is a "start boost coil".  In  the CJ6 manuals it is a "starting ignition coil". The P/N is DH-2, it is located  on the LH firewall readily identified by the HT lead to the LH mag.

 It is an absolutely exact copy of the original  Bendix/Scintilla

 unit from the 1940's.

  

 Walt

 [quote]   ---

wlannon(at)persona.ca
Guest

Posted: Mon Jul 26, 2010 7:53 pm Post subject: CJ6 Hot Starts

Paul;

  

 That is true and is surely slightly less of a  hazard than direct - to cylinder priming.  Depends on how much fuel and  evaporation time.  As soon as engine rotation starts the destination is the  cylinders with the blower turning at 7.87:1 for the Huosai.

  

 Walt

 [quote]   ---

ph451(at)yahoo.com
Guest

Posted: Mon Jul 26, 2010 8:50 pm Post subject: CJ6 Hot Starts

Walt,

  

 What do you mean by "after filling the primer?"



--- On Tue, 7/27/10, Walter Lannon <wlannon(at)persona.ca> wrote:



 [quote]

From: Walter Lannon <wlannon(at)persona.ca>

Subject: Re: CJ6 Hot Starts

To: yak-list(at)matronics.com

Date: Tuesday, July 27, 2010, 4:02 AM



 --> Yak-List message posted by: Walter Lannon <wlannon(at)persona.ca (wlannon(at)persona.ca)>



Your problem is simple. It is pretty severe over priming.

You are trying to fire up a air/fuel mixture with a ratio of maybe 3:1 (?) instead of about 14:1.  You are also washing the cylinder walls of oil which is already thinned out by the high temperature and increasing the possibility of hydraulic lock with excess fuel.



In the conditions you describe I use 1 or 2 shots after filling the primer for the Huosai and the M14P.  Works every time.  For the R1340 I use 1/2 shot after filling the primer (large barrel type).



In addition I never pull the prop through while priming.  I put that in the same category as Russian roulette.  If you have a failed mag. switch, a disconnected or a broken "P"

lead  you have a live mag. and are flirting with disaster.



Walt



---

viperdoc(at)mindspring.co
Guest

Posted: Tue Jul 27, 2010 4:18 am Post subject: CJ6 Hot Starts

When you first start pushing the primer in the pressure is low. If you open the intake drain and watch for fuel to start to drip out it takes about 3 to 5 cycles on the primer pump on the cylinder side to feel the pressure increase in the primer handle (resistance to pushing). Now watch the intake drain as you continue to pump. It takes 2 more strokes to see a small amount of fuel to start flowing from it. Push in the full 6 strokes and watch the stream that forms flowing out of the drain.  

Doc  

     

From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Paul Hamlin

 Sent: Monday, July 26, 2010 11:50 PM

 To: yak-list(at)matronics.com

 Subject: Re: CJ6 Hot Starts  

  

              

Walt,   

      

    

      

What do you mean by "after filling the primer?"

   

   --- On Tue, 7/27/10, Walter Lannon <wlannon(at)persona.ca>   wrote:   

   [quote]   



   From: Walter Lannon <wlannon(at)persona.ca>

   Subject: Re: CJ6 Hot Starts

   To: yak-list(at)matronics.com

   Date: Tuesday, July 27, 2010, 4:02 AM      

--> Yak-List message posted by: Walter Lannon <wlannon(at)persona.ca>

   

   Your problem is simple. It is pretty severe over priming.

   You are trying to fire up a air/fuel mixture with a ratio of maybe 3:1 (?)   instead of about 14:1.  You are also washing the cylinder walls of oil   which is already thinned out by the high temperature and increasing the   possibility of hydraulic lock with excess fuel.

   

   In the conditions you describe I use 1 or 2 shots after filling the primer   for the Huosai and the M14P.  Works every time.  For the R1340 I   use 1/2 shot after filling the primer (large barrel type).

   

   In addition I never pull the prop through while priming.  I put that in   the same category as Russian roulette.  If you have a failed mag.   switch, a disconnected or a broken "P"

   lead you have a live mag. and are flirting with disaster.

   

   Walt

   

   

   

   ---

mark.bitterlich(at)navy.m
Guest

Posted: Tue Jul 27, 2010 8:09 am Post subject: CJ6 Hot Starts

Walt, his problem may have been over-priming.  Mine is certainly not.

I also do not think his was either to be honest.  This is not a person

who has never started a hot engine before, and the problem he is having

is something that just started.  



Mark Bittelich



 



--

mark.bitterlich(at)navy.m
Guest

Posted: Tue Jul 27, 2010 8:12 am Post subject: CJ6 Hot Starts

Thanks Dennis! 



Mark 



P.s.  I'll try your way!  

 



--

mark.bitterlich(at)navy.m
Guest

Posted: Tue Jul 27, 2010 8:20 am Post subject: CJ6 Hot Starts

Some call it TOMATO  Some call it TOOMATOO, what-ever.  



If you really want to be accurate, let's call it a Model "T" Vibrator

Coil.  



In any case, this is a coil that is stand alone and uses a square wave

input in order to generate a secondary output from a transformer.  The

square wave is generated by a BUZZER with electrical contacts that makes

and breaks a 28 VDC input.  This produces a steady stream of spark

energy that is in no way controlled by internal MAG components, like

points, etc.  The internal MAG coil is not used, the internal MAG points

are not used, the Internal MAG Cigarette is not used.  The spark energy

is fed directly to the ROTOR and as the ROTOR spins a steady stream of

spark energy jumps to each spark plug in turn.  In truth the engine

should be able to RUN on this energy alone.  Not very well, because on a

M-14 it is very much retarded, but it will in fact run.   



Whatever you want to call it is fine with me, but most people understand

it when you call it a SHOWER OF SPARKS.  BOOSTER COIL is fine too, but

it sure is not BOOSTING anything as far as I can see, so it is a simple

matter of nomenclature.  OK?  Walt is correct in that the people that

made this unit for 1940 engines called it a "Booster Coil".  He's right.

It does BOOST the 28 volts way up there.  It then provides a continious

"shower of sparks" as the rotor turns.  So it is a BOOSTER COIL that

produces a SHOWER OF SPARKS... Or if not that... A WHOLE LOT OF SPARKS

JUST WAITING TO GET THERE.  Whatever.  



The point gap will influence the length of the square wave which will in

turn impact the strength of the field as it builds.  The longer the time

period of the square wave, the bigger the transformer flux field will

build.  If you go too much, the field will already be at maximum and you

will just start flowing excess current through the coil heating it.  Be

nice to be able to look at it somehow with a measurement and be able to

go for the max.  Just not sure how to do that.  I think just LOOKING at

it may be in fact the best solution. 



Mark 



--

wlannon(at)persona.ca
Guest

Posted: Tue Jul 27, 2010 11:22 am Post subject: CJ6 Hot Starts

Hi Paul;

  

 Operate the primer until you feel a definite  resistance to the down stroke.

 If the primer is in good shape - no leaking ball  valves, etc. it should take about 3 strokes

 Do the upstroke slowly for best  results

  

 Cheers;

 Walt

 [quote]   ---

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