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Over-priming

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richard.goode(at)russiana
Guest

Posted: Thu Sep 17, 2009 8:13 am Post subject: Over-priming

Over-priming  

  

 We have just lost a Sukhoi in Europe, after  over-priming on start-up.  

  

 We have had several before, leading to  scorched engines and cowlings, but, in this case, the aeroplane was totally  destroyed.  

  

 So be warned, and only prime to the extent  that is absolutely necessary to start.  Also, if a fire does start, then it  is vital to keep cranking the engine over, even if it does not  start.   This will suck excess fuel and vapour into the engine, and  probably put the fire out if it is small.  

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



   [quote][b]

mark.bitterlich(at)navy.m
Guest

Posted: Thu Sep 17, 2009 9:21 am Post subject: Over-priming

For what it is worth....  



All M-14's that I deal with have the intake drain kit installed.

Typically I prime the engine with that drain left OPEN.  I pull the prop

through after priming and at the same time......if I have over-primed

the engine, the excess fuel simply runs out the intake drain.  I suppose

that it is possible that you could fill a cylinder up with fuel anyway,

but it's pretty hard to do.. .and it has never happened to me, and I do

tend to over-prime.  Of course I close it before starting... But it

remains an effective way to keep from SERIOUSLY over-priming the engine.

I offer it only as a thought, but it does work for me. 



Mark Bitterlich



--

Dabear(at)damned.org
Guest

Posted: Thu Sep 17, 2009 12:42 pm Post subject: Over-priming

It is interesting how much difference their is with starting techniques for 

the M14P (and the 285).  I don't recommend all the getting up and down 

between the cockpit (priming, pulling through, etc)



I've put 700 hours on the M14P between my yak-52 and the CJ.  I've always 

started it the same and it "almost always" starts on the 2nd or 3rd blade 

unless there is an issue (nitrogen only in the system, mags off in the back, 

etc).  I believe if the air distribution system and spark system is correct 

on the M14P, it will start just fine by

1.  Pulling through (checking for H-lock)

2.  Closing the intake drain

3.  Getting in the cockpit

4.  Fuel pressure (wobble pump)

5.  Prime 3 times (with fuel; it make take a shot or two for the primer to 

fill with fuel); plus 1 shot of prime for every 10degC below 50 of Oil temp)

6.  Hit the starter, and turn the mags on after she starts.



The only thing I've changed over the years is to leave the primer in the 

cocked position (not directly strait) until the engine is fully started.  I 

then move it to the locked position.



That is my opinion, your mileage may vary.

Dabear

---

dsavarese0812(at)bellsout
Guest

Posted: Thu Sep 17, 2009 1:45 pm Post subject: Over-priming

Do you have the throttle completely closed when you hit the  start button the first time?

  

 Dennis

 [quote]   ---

william(at)netpros.net
Guest

Posted: Thu Sep 17, 2009 5:56 pm Post subject: Over-priming

I recall the manual says to follow this procedure for cold start 

priming/starting:



   1. Three strokes set to pipe

   2. Three blades

   3. Three strokes set to pipe

   4. Three blades

   5. Three strokes set to pipe

   6. Three strokes set to main

   7. Push the start button.

   9. Mags to both when she catches, stroke on main if needed.

10. Prime to middle/locked position.



Could that over prime the engine?



At 10:21 AM 9/17/2009, Bitterlich, Mark G CIV Det Cherry Point, 

MALS-14 64E wrote:

 	  Quote: 	
		  

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

For what it is worth....



All M-14's that I deal with have the intake drain kit installed.

Typically I prime the engine with that drain left OPEN.  I pull the prop

through after priming and at the same time......if I have over-primed

the engine, the excess fuel simply runs out the intake drain.  I suppose

that it is possible that you could fill a cylinder up with fuel anyway,

but it's pretty hard to do.. .and it has never happened to me, and I do

tend to over-prime.  Of course I close it before starting... But it

remains an effective way to keep from SERIOUSLY over-priming the engine.

I offer it only as a thought, but it does work for me.

richard.goode(at)russiana
Guest

Posted: Fri Sep 18, 2009 6:23 am Post subject: Over-priming

There seem to be a lot of methods for  priming - by definition, they cannot all be correct.   It does help to  understand how the system works:

  

 There are two positions on the priming  pump:

  

    Cylinder, and    line (sometimes also written as    system).    
Excessive priming into the cylinder will    over-prime, and that can have serious effects!     
Priming into line / system is simply    priming the carburettor and building up fuel pressure.   You can do    this all day, and excess fuel simply returns back from the carburettor.        
The Russian manuals are misleading in that    they are all geared to having an external engineer to turn the    propeller.   Of course this is fine if you have such a person, but    most of us do not, and it really is most inconvenient to keep hoping in    and out of the cockpit, and quite simply, it is not necessary. So the correct procedure is:

  

    Turn the prop at least 10 complete    revolutions to avoid hydraulic-lock.     
In the aeroplane, select line/system, and    pump a good number of times.  I say a number of times, simply because in    hot weather etc you can get air in the system, and given that it does not    matter if you over-prime on line/system, you want to make sure that each pump    is totally fuel and not air before priming onto cylinder.    
Prime onto cylinder - between 3 and 5    primes is all you need.   More than 5 and you are almost certainly    over- priming.     
Check that you still have good fuel    pressure from the priming to line/system; if not, a couple more pumps on    the line/system to build it up.      
Set throttle.    
Start with magnetos off, and then on when    it fires.     
Having left the primer out, but on the    cylinder side, as soon as if fires give it one pump - possibly more in    cold weather, but again no more than that.     
Keep the engine running on the throttle.       
Lock primer.  Of course if you have someone outside to  turn the prop through 2/3 revolutions while the cylinders are being primed, this  is helpful, but not necessary.   

  

 IF however air is low, then it is worth  while sucking in while priming, or if by your self (having checked everything is  off) having primed on cylinder then do the priming.  

  

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



   [quote][b]

Dabear(at)damned.org
Guest

Posted: Fri Sep 18, 2009 6:24 am Post subject: Over-priming

Sorry I missed that.  yes, throttle open about  3/4 of on inch.

  

 Dabear

 [quote]   ---

dsavarese0812(at)bellsout
Guest

Posted: Fri Sep 18, 2009 6:47 am Post subject: Over-priming

Ahhh.  That's what I thought.  Just like we used to  start a carbureted engine in our cars when we were younger.  

 Dennis

 [quote]   ---

jblake207(at)COMCAST.NET
Guest

Posted: Fri Sep 18, 2009 6:51 am Post subject: Over-priming

Dennis, What was it like working on the first Ford assembly line?  JB 



---

terrycalloway(at)mac.com
Guest

Posted: Fri Sep 18, 2009 7:22 am Post subject: Over-priming

There is a difference in the Yak and CJ primers.  Can someone offer additional discussion on priming an M-14 installed on the CJ?  I believe the Yak primer is also the wobble pump which is the difference in Cylinder and Line which you mention.  Is this correct?Thanks;

tc



On Sep 18, 2009, at 9:19 AM, Richard Goode wrote:

 	  Quote: 	
		  There seem to be a lot of methods for priming - by definition, they cannot all be correct.   It does help to understand how the system works:

 

There are two positions on the priming pump:

 

Cylinder, and line (sometimes also written as system).
Excessive priming into the cylinder will over-prime, and that can have serious effects! 
Priming into line / system is simply priming the carburettor and building up fuel pressure.   You can do this all day, and excess fuel simply returns back from the carburettor. 
The Russian manuals are misleading in that they are all geared to having an external engineer to turn the propeller.   Of course this is fine if you have such a person, but most of us do not, and it really is most inconvenient to keep hoping in and out of the cockpit, and quite simply, it is not necessary.So the correct procedure is:

 

Turn the prop at least 10 complete revolutions to avoid hydraulic-lock. 
In the aeroplane, select line/system, and pump a good number of times.  I say a number of times, simply because in hot weather etc you can get air in the system, and given that it does not matter if you over-prime on line/system, you want to make sure that each pump is totally fuel and not air before priming onto cylinder.
Prime onto cylinder - between 3 and 5 primes is all you need.   More than 5 and you are almost certainly over- priming. 
Check that you still have good fuel pressure from the priming to line/system; if not, a couple more pumps on the line/system to build it up.  
Set throttle.
Start with magnetos off, and then on when it fires. 
Having left the primer out, but on the cylinder side, as soon as if fires give it one pump - possibly more in cold weather, but again no more than that. 
Keep the engine running on the throttle.
Lock primer.Of course if you have someone outside to turn the prop through 2/3 revolutions while the cylinders are being primed, this is helpful, but not necessary.  

 

IF however air is low, then it is worth while sucking in while priming, or if by your self (having checked everything is off) having primed on cylinder then do the priming. 

 

 

Richard Goode Aerobatics 

Rhodds Farm 

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

 

Tel: +44 (0) 1544 340 120

Fax: +44 (0) 1544 340 129 

www.russianaeros.com



 	  Quote: 	
		  



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richard.goode(at)russiana
Guest

Posted: Fri Sep 18, 2009 8:20 am Post subject: Over-priming

To Clarify:

  

 My earlier posting refered ONLY  to Yaks - I have no experience of CJ's. 

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



   [quote][b]

nigel(at)yakdisplay.com
Guest

Posted: Fri Sep 18, 2009 1:53 pm Post subject: Over-priming

That's exactly how I start my 52 and it works every time resulting in no drama, and much less wear on the engine than other methods since the engine starts and runs at smooth idle rather than bursting into life at high rpm.  

Nigel Willson





On 18 Sep 2009, at 15:19, "Richard Goode" <richard.goode(at)russianaeros.com (richard.goode(at)russianaeros.com)> wrote:



[quote]  There seem to be a lot of methods for  priming - by definition, they cannot all be correct.   It does help to  understand how the system works:

  

 There are two positions on the priming  pump:

  

    Cylinder, and    line (sometimes also written as    system).    
Excessive priming into the cylinder will    over-prime, and that can have serious effects!     
Priming into line / system is simply    priming the carburettor and building up fuel pressure.   You can do    this all day, and excess fuel simply returns back from the carburettor.        
The Russian manuals are misleading in that    they are all geared to having an external engineer to turn the    propeller.   Of course this is fine if you have such a person, but    most of us do not, and it really is most inconvenient to keep hoping in    and out of the cockpit, and quite simply, it is not necessary. So the correct procedure is:

  

    Turn the prop at least 10 complete    revolutions to avoid hydraulic-lock.     
In the aeroplane, select line/system, and    pump a good number of times.  I say a number of times, simply because in    hot weather etc you can get air in the system, and given that it does not    matter if you over-prime on line/system, you want to make sure that each pump    is totally fuel and not air before priming onto cylinder.    
Prime onto cylinder - between 3 and 5    primes is all you need.   More than 5 and you are almost certainly    over- priming.     
Check that you still have good fuel    pressure from the priming to line/system; if not, a couple more pumps on    the line/system to build it up.      
Set throttle.    
Start with magnetos off, and then on when    it fires.     
Having left the primer out, but on the    cylinder side, as soon as if fires give it one pump - possibly more in    cold weather, but again no more than that.     
Keep the engine running on the throttle.       
Lock primer.  Of course if you have someone outside to  turn the prop through 2/3 revolutions while the cylinders are being primed, this  is helpful, but not necessary.   

  

 IF however air is low, then it is worth  while sucking in while priming, or if by your self (having checked everything is  off) having primed on cylinder then do the priming.  

  

  

 Richard Goode Aerobatics 

Rhodds Farm  

Lyonshall

Herefordshire

HR5 3LW 

United Kingdom

  

 Tel: +44 (0) 1544 340 120

Fax: +44 (0)  1544 340 129 

www.russianaeros.com



    	  Quote: 	
		  

	


[b]

william(at)netpros.net
Guest

Posted: Fri Sep 18, 2009 2:20 pm Post subject: Over-priming

Hmmm   ... well there goes my excuse for getting excercise, hopping up onto the wing twice before I actually climb on board!



I'll try this approach tomorrow and report how it goes ... 

+--

dsavarese0812(at)bellsout
Guest

Posted: Fri Sep 18, 2009 4:22 pm Post subject: Over-priming

Yes, that is correct Terry.  The Yak uses the primer pump  for both functions: pressurize the fuel system by rotating the primer pump to  the left and pumping until adequate fuel pressure can be seen on the fuel  pressure gauge.  Turning the primer pump to the right and pumping primes  the engine.

  

 On the CJ, the wobble pump performs the same function as  turning the Yak's primer pump to the left and pumping - pressurizing the fuel  system.  The CJ's primer pump on the right console is identical to the Yak  primer pump turned to the right.  On the CJ, this primer pump can be turned  to the left or right to prime the engine.  Whereas on the Yak it must be  turned to the right to prime the engine.

 Dennis

  

 [quote]   ---

dsavarese0812(at)bellsout
Guest

Posted: Fri Sep 18, 2009 4:22 pm Post subject: Over-priming

Pretty tough.  12 hour days and only $14 a week salary.  

 Dennis

 [quote]   ---

mark.bitterlich(at)navy.m
Guest

Posted: Mon Sep 21, 2009 6:22 am Post subject: Over-priming

Strange as it may seem... On the YAK-52 you turn it to the right to

prime the engine, on my YAK-50, you turn it to the LEFT to prime the

engine.  It all gets very confusing.  I've always kind of wondered if it

is just MY 50 that is backwards from everyone else!  



Doc?   Tom?  



Mark Bitterlich



--

richard.goode(at)russiana
Guest

Posted: Mon Sep 21, 2009 6:49 am Post subject: Over-priming

I believe that ALL Yak 50s have the primer  positions reversed!!No idea why,since there is no technical reason I can think  of that would make them want to change.

 Richard

  

 Richard Goode Aerobatics

Rhodds Farm

Lyonshall

Hereford

HR5  3LW

United Kingdom

  

 Tel:   +44 (0) 1544 340120

Fax:  +44 (0) 1544  340129

www.russianaeros.com



 [quote]   ---

pilko2(at)btinternet.com
Guest

Posted: Mon Sep 21, 2009 7:53 am Post subject: Over-priming

Nope, that's the way they are !



kp 



--

viperdoc(at)mindspring.co
Guest

Posted: Mon Sep 21, 2009 9:39 am Post subject: Over-priming

Same for my 50 as yours, prime the main to the left.

Doc



--

tigeryak18t

Joined: 26 Sep 2009
Posts: 233
Location: PARIS FRANCE

Posted: Sun Sep 27, 2009 12:41 pm Post subject: Re: Over-priming

to all,



I just discovered tonight this passionnating list. So if I can bring my own experiance on my Yak18T.

I have experienced the Richard Goode system during winter time (-20degre centigrade) and summer time (+35 degre centigrade) and it works perfectly well. It always started at the very first blades. So here is how it works.

First turn 10 blade to be sure that you will have no HL. 10 is 9 cylinders plus one to be sure.



Then enter the plane and prime (on the right for the 18T) three time, then go down and turn about three or four blades (in fact until you feel the blades much more easy to turn).



Then go back in the plane and prime one time



then hop down and again two blades. 



Then enter the plane and turn the pump left to build pressure. As Richard say it can be tough in summer due to air in the system. 



Then when you reached the right pressure, turn right and pump two or three time....then fire (in winter up to five time but I never did as much)



In winter under zero I would recommand to warm the motor with an external heater source. But if you can't. the only thing that changes is the number of primer pump after the first cycles.



Hope that can help



kind regards



Didier Tiger Yak in Paris

_________________
Didier Tiger YAK18T
Member of Commemorative Air Force
French Wing

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