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billlang(at)live.com.au
Guest

Posted: Thu Sep 16, 2010 10:06 pm Post subject: Starting Problems Yak 52

I am having trouble starting my Yak 52. I originally had problems with the air starter, and we had to prop start the engine, usually on second or third pull. . Now that the starter is fixed, we seem to be having some fuel problems. I am using up all of the air in the bottle and still no start. Eventually we can get a pull start. I have installed the oil drain kit, and after turning the engine over, fuel is accumulating in the manifold. A large amount of fuel runs out of the drain when opened.. This is what we are seeing. 

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />  

Pressurising the fuel system with primer to the left, about 10 strokes, to get pressure registering. However, the fuel pressure drops off almost immediately, unlike our other Yak. 

  

About 5 strokes to the right to prime the cylinders, sometimes pulling the prop a blade between strokes, all as per recommended procedure. Ambient air temp about 18C, and we are careful to not overprime. 

  

Using the air starter, after about 10 rotations and with mags on both it still  won’t start. On checking the oil drain cock, fuel runs out, maybe 50 to 100 mls. We are basically repeating that until running out of air, and then topping up with external AIR bottle. 

  

When we can eventually get it going by pull start, it runs and flies well. It starts using the air starter, (reluctantly) when warm. On shutdown, and on opening the drain cock, again fuel comes out. 

  

It seems we are flooding the engine and we suspect it may be something within the carburettor that is sticking. Thoughts anyone? We have the carburettor cutaway poster, and the M14p Maint manual to guide us, but the mechanic is reluctant to open the carbie without knowing that this is the most likely cause, and if there is a simple fix to clean a possibly sticky needle valve, if that is what it could be? 

  

If anyone has had similar problems, you help is much appreciated 

  

Cheers  

  

Bill Lang 		 	   		    [quote][b]

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radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Fri Sep 17, 2010 12:04 am Post subject: Starting Problems Yak 52

Sounds like the shower of sparks or the wire from it to the left magneto to me. Has that part been checked?

On Sep 17, 2010, at 2:01 AM, Bill Lang wrote:

 	  Quote: 	
		  I am having trouble starting my Yak 52. I originally had problems with the air starter, and we had to prop start the engine, usually on second or third pull. . Now that the starter is fixed, we seem to be having some fuel problems. I am using up all of the air in the bottle and still no start. Eventually we can get a pull start. I have installed the oil drain kit, and after turning the engine over, fuel is accumulating in the manifold. A large amount of fuel runs out of the drain when opened.. This is what we are seeing.

 

Pressurising the fuel system with primer to the left, about 10 strokes, to get pressure registering. However, the fuel pressure drops off almost immediately, unlike our other Yak.

 

About 5 strokes to the right to prime the cylinders, sometimes pulling the prop a blade between strokes, all as per recommended procedure. Ambient air temp about 18C, and we are careful to not overprime.

 

Using the air starter, after about 10 rotations and with mags on both it still  won’t start. On checking the oil drain cock, fuel runs out, maybe 50 to 100 mls. We are basically repeating that until running out of air, and then topping up with external AIR bottle.

 

When we can eventually get it going by pull start, it runs and flies well. It starts using the air starter, (reluctantly) when warm. On shutdown, and on opening the drain cock, again fuel comes out.

 

It seems we are flooding the engine and we suspect it may be something within the carburettor that is sticking. Thoughts anyone? We have the carburettor cutaway poster, and the M14p Maint manual to guide us, but the mechanic is reluctant to open the carbie without knowing that this is the most likely cause, and if there is a simple fix to clean a possibly sticky needle valve, if that is what it could be?

 

If anyone has had similar problems, you help is much appreciated



 Cheers



 Bill Lang

 	  Quote: 	
		  



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dsavarese0812(at)bellsout
Guest

Posted: Fri Sep 17, 2010 3:47 am Post subject: Starting Problems Yak 52

Bill,

 You wrote "Using the air starter, after about 10  rotations and with mags on both it still won’t start."  Is this a  Yak 52TW or standard Yak?  Do you know if you have M9F mags or the M9-35  centrifugal advance mags.  If it is a TW, then yes it should be started  with the mags on because the PF engine has M9-35 mags.  For the standard  Yak 52/M14 with M9F mags, the proper starting procedure is to  start the engine with the mags OFF.  Once the engine fires with the  starting coil, THEN switch the mags to the on position.  But it has to  fire on the starting coil first.  If the starting coil (also called the  "shower of sparks") does not fire the engine within the first or second blade  after you press the start button, don't keep holding the start button.  All  you're doing is wasting air.  It is not like an electric start.  While  it is rotating though, assuming it doesn't fire with the shower of sparks, you  can switch the mags from the OFF position to BOTH quickly.  Sometimes the  engine will start.  The key is getting the rotation before you switch to  BOTH.  But with a standard Yak 52/M14 engine with M9F mags, don't try to  start it with the mags in BOTH.  It could easily kick back or attempt to  run backwards.  Then you might be changing the air compressor sheer  coupling....another 6 hours of work.

  

 Have you checked the spark from the starting coil?   If not, as Eric said, a bad starting coil or wire from the starting coil to the  left mag cap could also be contributing to the problem.

  

 Contact me off-list if you would like for me to describe  a procedure for checking the starting coil/wire.

 Dennis

 dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net).

 [quote]   ---

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jblake207(at)comcast.net
Guest

Posted: Fri Sep 17, 2010 5:51 am Post subject: Starting Problems Yak 52

Dennis, <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 

  

HELP!!  How do I remove my name from the YAK List?     

  

Thanks, 

Jon 



---

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mark.bitterlich(at)navy.m
Guest

Posted: Fri Sep 17, 2010 8:05 am Post subject: Starting Problems Yak 52

It is not unusual after giving it FIVE strokes of prime, to have the

excess fuel run out of your intake drain outlet.  It is very hard to

over-prime the engine IF, and I repeat IF, you have an intake drain kit

installed and the intake drain is clear of oil.  In fact, that is one of

the thing I check on starting.  When I give it a few strokes of prime, I

EXPECT to see fuel coming out of the intake drain outlet.  If I don't,

then there is probably a lot of oil in there and I need to rethink

starting the engine.  



Question, do you have the automotive plug conversion?  If so, when was

the last time you changed the plugs and what is the GAP setting?  If you

are using automotive plugs, make sure the gap is about .018 to .020  



Agreed that the BOOST COIL (shower of sparks... My favorite discussion

   is highly suspect.  HIGHLY SUSPECT.  If the engine RUNS ... Then

you probably do NOT have a pressure carb problem.  Especially if you can

manually prop the engine.  



Don't worry about system pressure falling to zero ... Mine always has.

Never an issue.  



Fuel coming out of the INTAKE DRAIN after the engine runs means that you

did not have it open AS YOU WERE PRIMING BEFORE START, and the excess

fuel collected in the intake drain hoses and remained there for the

whole time.  This is NORMAL.  Mine does the exact same thing.  The way

to avoid that is to have the INTAKE DRAIN OUTLET PETCOCK OPEN as you are

priming.  Prime it, and then pull the engine through.  You will get fuel

coming out of the intake drain, as I have said.  This is a very good

method to AVOID over-priming.  It becomes almost impossible to do,

because the excess fuel has no place to collect, and just drains out the

bottom.  I have been doing it that way for 10 years.  



You should not start the engine with the MAGS ON BOTH using the air

starter.  Yes, it can work, but it can also cause some damage if you

happen to get unlucky.  Hand propping, .... Should also be done with the

shower of sparks, but it seems clear that IT IS NOT WORKING.  



A good mech should be able to tell you how to check that.  But I have

had the same problems and it can be a real pain in the butt to

troubleshoot.  There are some articles written on how you can ADJUST the

shower of sparks vibrator coil POINTS to make it work better.  If all

else fails, check the wire from it to the mag, and then buy a new shower

of sparks unit from Doug Sapp.  The CJ-6A and M-14's units are

IDENTICAL.  



Turn off the main air valve... Run the flaps up and down to drain out

any residual air.  Now push the start button and listen for the BUZZ.

How loud is it?  A safe test... The shower of sparks goes to the mag on

the left which on my 50 is the front plugs.  Pull all the front plugs.

Now the engine is safe.  Take one of the plug wires and hold it about

1/4 inch from a ground.  Push the starter button and rotate the prop

manually until it gets to that wire and LOOK AT THE SPARK!  You can also

do this by leaving the wire connected to the plug and then holding the

plug case to ground and then looking at the actual spark on the spark

plug itself.  See how strong it is.  If it is not really actively

BRIGHT, then you have found the problem.  You can adjust the booster

coil contacts and try to make the spark stronger.  



Odd are about 80% that this is your problem.  Not the carb. 



Mark

 



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billlang(at)live.com.au
Guest

Posted: Fri Sep 17, 2010 3:30 pm Post subject: Starting Problems Yak 52

 

  [quote]Thanks Mark, Richard, Dennis et al for your lengthy and considered replies. Will look at shower of sparks Bill



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[b]

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radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Sat Sep 18, 2010 4:51 am Post subject: Starting Problems Yak 52

I do the same thing. Drains open. Pull through 8+ blades. Preflight.  

Pressurize carb monitoring fuel pressure gage (not even sure if that's  

needed), 2 strokes, 2 blades, 2 strokes, 2 strokes... and then I will  

see a trickle of fuel... then 4+ strokes. When starting, I re- 

pressurize carb (takes about 1 stroke, and leave the primer out on  

prime (right side on the 52). I will then give it a shot if needed  

before start, and push it in after start if it didn't need it. Don't  

forget to lock it in the middle, or it will run rough and gobble fuel.  

If I have flown recently, priming between blades can be dispensed  

with, but don't forget to pull through at least 8 blades. If you JUST  

shut it off, you might skip it, but if it's been a few minutes and  

still hot, you don't want to touch the prop for a while.... it can  

fire on you, and some say it scores the pistons.

On Sep 17, 2010, at 12:01 PM, Bitterlich, Mark G CIV Det Cherry Point,  

MALS-14 64E wrote:



[quote] 

 Point, MALS-14 64E" <mark.bitterlich(at)navy.mil>



 It is not unusual after giving it FIVE strokes of prime, to have the

 excess fuel run out of your intake drain outlet.  It is very hard to

 over-prime the engine IF, and I repeat IF, you have an intake drain  

 kit

 installed and the intake drain is clear of oil.  In fact, that is  

 one of

 the thing I check on starting.  When I give it a few strokes of  

 prime, I

 EXPECT to see fuel coming out of the intake drain outlet.  If I don't,

 then there is probably a lot of oil in there and I need to rethink

 starting the engine.



 Question, do you have the automotive plug conversion?  If so, when was

 the last time you changed the plugs and what is the GAP setting?  If  

 you

 are using automotive plugs, make sure the gap is about .018 to .020



 Agreed that the BOOST COIL (shower of sparks... My favorite discussion

    is highly suspect.  HIGHLY SUSPECT.  If the engine RUNS ... Then

 you probably do NOT have a pressure carb problem.  Especially if you  

 can

 manually prop the engine.



 Don't worry about system pressure falling to zero ... Mine always has.

 Never an issue.



 Fuel coming out of the INTAKE DRAIN after the engine runs means that  

 you

 did not have it open AS YOU WERE PRIMING BEFORE START, and the excess

 fuel collected in the intake drain hoses and remained there for the

 whole time.  This is NORMAL.  Mine does the exact same thing.  The way

 to avoid that is to have the INTAKE DRAIN OUTLET PETCOCK OPEN as you  

 are

 priming.  Prime it, and then pull the engine through.  You will get  

 fuel

 coming out of the intake drain, as I have said.  This is a very good

 method to AVOID over-priming.  It becomes almost impossible to do,

 because the excess fuel has no place to collect, and just drains out  

 the

 bottom.  I have been doing it that way for 10 years.



 You should not start the engine with the MAGS ON BOTH using the air

 starter.  Yes, it can work, but it can also cause some damage if you

 happen to get unlucky.  Hand propping, .... Should also be done with  

 the

 shower of sparks, but it seems clear that IT IS NOT WORKING.



 A good mech should be able to tell you how to check that.  But I have

 had the same problems and it can be a real pain in the butt to

 troubleshoot.  There are some articles written on how you can ADJUST  

 the

 shower of sparks vibrator coil POINTS to make it work better.  If all

 else fails, check the wire from it to the mag, and then buy a new  

 shower

 of sparks unit from Doug Sapp.  The CJ-6A and M-14's units are

 IDENTICAL.



 Turn off the main air valve... Run the flaps up and down to drain out

 any residual air.  Now push the start button and listen for the BUZZ.

 How loud is it?  A safe test... The shower of sparks goes to the mag  

 on

 the left which on my 50 is the front plugs.  Pull all the front plugs.

 Now the engine is safe.  Take one of the plug wires and hold it about

 1/4 inch from a ground.  Push the starter button and rotate the prop

 manually until it gets to that wire and LOOK AT THE SPARK!  You can  

 also

 do this by leaving the wire connected to the plug and then holding the

 plug case to ground and then looking at the actual spark on the spark

 plug itself.  See how strong it is.  If it is not really actively

 BRIGHT, then you have found the problem.  You can adjust the booster

 coil contacts and try to make the spark stronger.



 Odd are about 80% that this is your problem.  Not the carb.



 Mark

 --

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