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Jeffrey Dill

Joined: 23 Jul 2007
Posts: 52
Location: Pleasant view, TN

Posted: Thu Aug 09, 2007 4:46 pm Post subject: 582 engine adjustments

I wrote a message on 7 July entitiled "Finally I flew my airplane". This is an update and comments are welcomed. 



I traveled to Oshkosh and talked with folks. To address the apparant low reading airspeed indicator, It was suggested that I vent my static port behind the dash, rather than use my new Skystar static port tapped just under and forward of the left horz stab. I will do further testing prior to that.



I spent an afternoon with a friend of a friend who knows 2 cycle engines. To my surprise, we found the throttles clearly and visibly mis-matched at an intermediate position. I had matched them at near full open and at the idle stop. Either they are not moving up and down at the same rate, which would seem impossible, or the gremlins got hold of them after I initially set them.  Re-adjust made a big difference, stopping the skip at the high end completely. There was still an inconsistency at the low end (less than 3000RPM and more on that later). To me it seemed like a spark plug firing intermittantly. This guy called it "4 cycling" and said it was something 2 cycles do when the carbs need adjusting and it meant that a spark plug was firing only every other stroke. He noted that my throttle to carb linkage was imprecise. He saw that the fulcrum that splits one cable to three was cantilevered several inches and the arm would bend very slightly with throttle movement. He asked me to attach a brace to stop ancillary movement at that location, which I have since done. He sent me to these sites which I have seen before, but it has been a while .



http://www.ultralightnews.com/enginetroublshooting/techtips/techtips1.htm



http://www.ultralightnews.com/enginetroublshooting/techtips/techtips2.htm



Contained in these links are links for the recommended jetting settings. I may as well include that one: http://www.ultralightnews.com/enginemaintenance/bingjet.html

My jets are right, but I have questions about the air screw. The chart shows a setting of 1.0 for a 582. Does that mean one full turn from all the way in? The second link above contains this quote:



"This air screw changes the air/fuel mixture by changing the ratio of air to the idle jet circuit. Turning the screw out with lean the mixture while turning it in richens it.

After referring to the jet chart you have a position to start from.  With the engine warmed up and idling and the screw set to factory specs turn the screw out very slowly - the engine should start to pick up rpm as you lean the mixture out. If nothing happens the low speed jet is probably plugged, or the small atomizer hole located in the throat of the carb  on the engine side is blocked.

Once you have the engine idling at its highest and leanest setting using the air screw turn the screw back in 1/8 of a turn which will richen it up just enough for the best performance.

Note it is usually necessary to do this three or four  times a year, do to the difference in air that you get in spring/summer/fall/winter. Note that on the 582 Rotax I have found that 45 and 50 idle jet work better than the standard 55 especially in winter. On the 582 the lower jet sizes have been shown to improve starting and help eliminate the rough idle."



I might have trouble finding a volunteer to turn those screws while the engine is running.



I asked several questions at Oshkosh about shimming a GSC prop due to tracking beyond recommended limits of 1/8 inch. I found one person who had shimmed due to tracking, and he said that he never noticed vibration when it was out of track, but he shimmed to make it right. I have since added a .010 shim of copper, per Rick at GSC and made my tracking right as well, but the vibration, presumed 4 cycling, persists below 3000 RPM.  Another distractor regarding vibration is the old flat plate engine mount design. Can anybody provide information about why the flat plate was upgraded to another arrangement? 



When we first started the engine, some months ago, and pitched the prop, we put a strobe on the blades to check the RPM against the tach. With no reason to think it was off, the two disagreed so bad we thought we were doing the gearbox conversion wrong or that the strobe was off.  There are different pitfalls when you make rebuilding an airplane your project, rather than building from scratch. After too much delay,  I borrowed another strobe tach and compared. The two strobe tachs agreed and the engine tach was reading, fortunately, too high. I am lucky. I thought I had set my prop for 6200 on takeoff, but it was turning more like 5500.  I am thinking this might be part of my cooling problem, too much pitch?  Thoughts? Would too much pitch tend to overheat my engine? Above links suggest that I am flirting with engine failure with too much pitch, but you guys chat about different settings, so how much latitude do I get?



On the subject of temp trouble, one person suggested that I lower the radiator. I asked the guys at Oshkosh (Lockwood) what is the highest temp allowed, I had also asked Ronnie at South Mississippi. Both said that 190 was getting up there with no firm number other than immediate action required at 200. Mine is always below 185, but the maintenance manual says 80deg C and converts it to 180 F. I will re-pitch the prop regardless and maybe that will make it run cooler. If not, I may lower the radiator or try a 95% water solution as suggested by the first link above. Here is the quote on that:



"Coolant: In order to run a liquid cooled engine we have to install coolant. Rotax recommends on the two stroke engines that a 50/50 antifreeze and water mixture be used. The antifreeze MUST be one that is aluminum compatible and the water used must be distilled. In summer applications I recommend a 95 % water - 5% antifreeze solution - this is considerably more efficient especially in hotter climates."

_________________
Jeff Dill
Model 2

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Wed Aug 22, 2007 2:01 pm Post subject: Re: 582 engine adjustments

a 2 stroke engine will "4 cycle" if the mixture is way rich!  that is the only way a 2 stroke will "4 cycle".



Having too much pitch will also put a heavy load on your engine and will indeed cause it to run hotter.  nIf you are using the stock RPM gauge they are known to be out of calibration something fierce.  Most seem to like the tiny tach and it seems to hold calibration just fine and matches very close to the optical tach.



Is there anyone around your area that is familiar with 2 strokes that can help tune it?

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

john beirne

Joined: 02 Oct 2006
Posts: 24
Location: Ireland

Posted: Wed Aug 22, 2007 3:43 pm Post subject: Re: 582 engine adjustments

Recently had a similar problem with a rough running engine below 4000rpm and in order to adjust the carbs I removed the propeller, and ran the engine safely, taking care not to bring the revs up high with no prop loading

Jeffrey Dill

Joined: 23 Jul 2007
Posts: 52
Location: Pleasant view, TN

Posted: Wed Aug 22, 2007 6:14 pm Post subject: Re: 582 engine adjustments

Good stuff. I will consider running it without the prop to adjust the air screw by ear without getting sliced and diced. This guy who has looked at it once claims to be experienced with two cycles. He is an aircfraft owner and pilot but his experience has been on motorcycles and such. We ran the engine after moving the needle valve from the third notch to the second. After running the engine like that and looking at the spark plugs, he felt it was running too hot, and we put it back to the third notch. I flew it today after setting the pitch for 6200RPM static. I saw about 1050 on the EGT, which I hear is about right. I would say it ran cooler with the lower pitch, but the OAT was much cooler, and I still saw 180 deg F a time or two. The cloud above me sprinkled a bit on my windshield. Naturally I thought I had sprung a leak and high-tailed it home. It is still four cycling at the lower RPMs. We had messed with the air screw before, but after reading those aforementioned web pages, I reset them to one turn out. I think it is worse now. Are they still affecting the mixture in the 4000-5000 RPM range? I have to get above 5000 to guarantee no skipping. Thanks for your insights. I attached a picture for grins.

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_________________
Jeff Dill
Model 2

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Wed Aug 22, 2007 7:23 pm Post subject: Re: 582 engine adjustments

great looking bird!  The midrange is what seems to be off.  What jets are you running?  and when you look at the jet chart, are you looking at the one with our without the air intake silencer.  I have seen this happen...and the wrong jets were installed.  Of course, since this is a midrange problem, you could go for the in-flight mixture adjustment and your problem should dissapear, as well as being able to richen up a tad on decent to keep the EGT's under control.



Did you verify the idle RPM with the optical tach?



4-5 thousand is the midrange needle to the main jet area

Jeffrey Dill

Joined: 23 Jul 2007
Posts: 52
Location: Pleasant view, TN

Posted: Thu Aug 23, 2007 3:52 am Post subject: Re: 582 engine adjustments

"you could go for the in-flight mixture adjustment and your problem should dissapear"



I am unaware of this option. Are you talking about hardware to change the mixture in flight? I have not found many 582 flyers in New England and certainly no experts on carburation. The two guys I have hooked up with have not had this problem. 



We have referenced the chart more than once to verify the correct jetting, though I cannot say from memory which it is. Right now I am cooperating with this friend of a friend. He is focusing on syncronization of the two carbs. He feels that there is sufficient play in the throttle system to allow them to open at different rates. I have since added a brace to address the one location of play he was seeing (fulcrum location). I think he might be barking up the wrong tree since I have flown it since with same problem. But things have to be done methodically to rule things out and home in on the actual problem, so I will continue to cooperate with him as long as he is willing.



I wasn't watching the EGT yesterday on descent. I will go back to the book to see what the concern is there. I was doing the Vy check to get it out of phase 1, which had me going up and down. 

    By the way, I mentioned in the past that my airspeed was reading low as compared to GPS. I mentioned this to John McBean at Oshkosh and he said to vent the altimeter to the back side of the dash (I had installed a Skystar static port). So, yesterday, before takeoff, I loosened the tube to where I could do the rest by hand in flight. In level flight, at 50 MPH indicated, I reached back plucked the tube out and sure enough, the airspeed jumped right up to 55. Now what do I do with that nice Skystar installation, ferry it around forever?

_________________
Jeff Dill
Model 2

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Thu Aug 23, 2007 7:10 am Post subject: Re: 582 engine adjustments

http://www.powerchutes.com/asa.asp



For the inflight mixture adjustment.  I have noticed that when decending if you pull the power back to say 4000 RPM or even 3000 and point the nose down hill and let the prop drive the engine the EGT's will spike up to well over 1200.  This can be corrected by turning the mixture knobs out one turn and riching it or I add some pitch to the IFA IVO prop and load the engine just a tad and the EGT's drop right down.  The other option is to come off the power and slow the plane up a bit nose high and she will drop like a rock and EGTs stay under control.  The way the inflight mixture works is one turn of the knob is equal to dropping or rasing the neelde one clip.  It is a pretty slick system and works very well once you figure it out.

Mark.Napier(at)sciatl.com
Guest

Posted: Fri Aug 24, 2007 6:07 am Post subject: 582 engine adjustments

I've been using the HACMan from Greensky and I like it.  My grey-head

had the older style carbs but it wasn't too hard to drill them to add

the ported vacuum attachment. I did add a 1/16" orifice in the static

line to increase the adjustment range.  I try to keep the EGT's just

under 1100.



http://www.greenskyadventures.com/bing/HACmanFAQ.htm



http://www.dairyaire.net/hac/hac.htm

Regarding the idle, I went from the #55 idle jet to a #50 and then a #45

before I got a good idle.  Turn the bleeds screws out in unison 1/2

turns at a time and test the idle again.  At about 4 turns all the

adjustment is used up and you have to try the next leaner jet.  I would

up raising the jet needle by 1 notch to compensate for the mid range.



Remember to mechanically sync the carbs.  Easy to do.  Adjust the cable

length so that the lower edges of the slides reach the top at the same

time.  Then adjust the idle stops so the slides touch the bottom at the

same time.  A patient helper slowly working the throttle helps.  You can

hear which one touches 1st.  Obviously the engine isn't running.  BTW,

never run the engine w/o the prop on it; its too easy to toast the

motor, literally.  Without a load the engine will run way too lean and

cook the piston and rings.



Have fun with it,



Mark Napier

Time: 08:11:19 AM PST US

Subject: Re: 582 engine adjustments

From: "akflyer" <akflyer_2000(at)yahoo.com>

http://www.powerchutes.com/asa.asp



For the inflight mixture adjustment.  I have noticed that when decending

if you

pull the power back to say 4000 RPM or even 3000 and point the nose down

hill

and let the prop drive the engine the EGT's will spike up to well over

1200.

This can be corrected by turning the mixture knobs out one turn and

riching it

or I add some pitch to the IFA IVO prop and load the engine just a tad

and the

EGT's drop right down.  The other option is to come off the power and

slow

the plane up a bit nose high and she will drop like a rock and EGTs stay

under

control.  The way the inflight mixture works is one turn of the knob is

equal

to dropping or rasing the neelde one clip.  It is a pretty slick system

and works

very well once you figure it out.



--------

Leonard Perry

Soldotna AK

Avid &quot;C&quot; / Mk IV 

582 IVO IFA

Full Lotus 1260

95% complete

Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=130496#130496



 





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Mark.Napier(at)sciatl.com
Guest

Posted: Fri Aug 24, 2007 6:17 am Post subject: 582 engine adjustments

I meant to say I drilled one carb.  You only need one vacuum source.



--

msm_9949(at)yahoo.com
Guest

Posted: Fri Aug 24, 2007 8:37 am Post subject: 582 engine adjustments

Mark,

   

  I've got the HACMan installed too. I find that it takes alot of turns to make a few degrees difference in EGT's. How and where did you add that 1/16" orifice in static line?

   

  Also, I've done all the idle adjustments you mentioned: swapped down to #45 jets, adjusted air screws incrementally so that slides are now practically bottomed out, but still can't get idle below 2500 rpm. 

   

  So I've got a prop clutch that is perpetually engaged at idle unless  I pull out the choke. Only then will it slow down enough for clutch to disengage. I've learned to live with it but it does annoy me.

   

  Any suggestions?



"Napier, Mark" <Mark.Napier(at)sciatl.com> wrote:

   	  Quote: 	
		  I've been using the HACMan from Greensky and I like  it. My grey-head

had the older style carbs but it wasn't too hard to drill them to add

the ported vacuum attachment. I did add a 1/16" orifice in the static

line to increase the adjustment range. I try to keep the EGT's just

under 1100.



http://www.greenskyadventures.com/bing/HACmanFAQ.htm



http://www.dairyaire.net/hac/hac.htm

Regarding the idle, I went from the #55 idle jet to a #50 and then a #45

before I got a good idle. Turn the bleeds screws out in unison 1/2

turns at a time and test the idle again. At about 4 turns all the

adjustment is used up and you have to try the next leaner jet. I would

up raising the jet needle by 1 notch to compensate for the mid range.



Remember to mechanically sync the carbs. Easy to do. Adjust the cable

length so that the lower edges of the slides reach the top at the same

time. Then adjust the idle stops so the slides touch the bottom at the

same time. A patient helper slowly  working the throttle helps. You can

hear which one touches 1st. Obviously the engine isn't running. BTW,

never run the engine w/o the prop on it; its too easy to toast the

motor, literally. Without a load the engine will run way too lean and

cook the piston and rings.



Have fun with it,



Mark Napier

Time: 08:11:19 AM PST US

Subject: Re: 582 engine adjustments

From: "akflyer" 

http://www.powerchutes.com/asa.asp



For the inflight mixture adjustment. I have noticed that when decending

if you

pull the power back to say 4000 RPM or even 3000 and point the nose down

hill

and let the prop drive the engine the EGT's will spike up to well over

1200.

This can be corrected by turning the mixture knobs out one turn and

riching it

or I add some pitch to the IFA IVO prop and load the engine just a tad

and the

EGT's drop right down. The other option is to come off  the power and

slow

the plane up a bit nose high and she will drop like a rock and EGTs stay

under

control. The way the inflight mixture works is one turn of the knob is

equal

to dropping or rasing the neelde one clip. It is a pretty slick system

and works

very well once you figure it out.



--------

Leonard Perry

Soldotna AK

Avid "C" / Mk IV

582 IVO IFA

Full Lotus 1260

95% complete

Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=130496#130496

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Marco Menezes

Model 2 582 N99KX

  [quote][b]

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Fri Aug 24, 2007 9:25 am Post subject: 582 engine adjustments

At 07:17 AM 8/24/2007, you wrote:

 	  Quote: 	
		  I did add a 1/16" orifice in the static

line to increase the adjustment range.


	


Mark,

         I too have the HACman and am very pleased with it. Would you 

please expand on this modification? How much range did you start and 

end with? And which is the static line? Did you buy or make the orifice?



Thanks in advance,

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

Mark.Napier(at)sciatl.com
Guest

Posted: Fri Aug 24, 2007 11:35 am Post subject: 582 engine adjustments

If you look at the picture I posted before (it's on the forums page

http://forums.matronics.com/download.php?id=6568 ) you can see the line

coming away from the fitting on the air cleaner.  That is the static

pressure sense line.  I bought a vacuum restrictor orifice (white

plastic and brass) from the auto parts store and put it in-line so I

wouldn't have to turn the valve so many turns to make a change.   But I

found that as purchased the hole was too small and made the adjustment

too sensitive.  So I just drilled the little brass hole out to 1/16" and

tried it.  I also dropped my main jet from 185 down to 180 for the

summer and it seems to be about right.



About that high idle; if you have to add enrichment (choke) to make the

idle stable below 2500 then your idle may be too lean.  I run my GSC

prop at a high pitch (I only see about 5900RPM static) and I know that

makes the engine run rich.  BTW, that is a good test.  At any throttle

setting but full the enrichment lever will add gas through the idle

circuit.  So if you add fuel and the EGT's fall sharply and the engine

stumbles then you could try a little leaner assuming that the EGT's

don't go too high.  Also note that the midrange jet needle and needle

jet affect the idle.  You could try raising your needle one notch and

see if that helps.



Cheers,



Mark Napier

N246DR

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Mark.Napier(at)sciatl.com
Guest

Posted: Fri Aug 24, 2007 5:55 pm Post subject: 582 engine adjustments

I had one more brain cell fire while driving home.  I remembered listening to Tom Olenik on the ultraflightradio archives.  He said that in the early days they had a hard time getting the engines to idle.  One fix was to cut a rectangular slot in the back of the slides to let more air through.  The idea was to allow more charge into the cylinders at idle to compensate for the loading of the prop.  These carbs came from motorcycles engines that don't have a prop hanging on them at idle.  Now all the Bing carbs for Rotax aircraft engines come with slides that have a slot in the rear.  

  

 But now with the clutch, he had to file on the bottoms of the slides to get less air into the engine at idle; basically trying to undo the slot at the rear of the slide.  Your trying to get the engine to idle at 1800 rpm or less with no load and that's much less power (fuel air mix) than the carb is currently set up for.

  

 You might ask one of the companies that sell the clutch how they set up their engines.

  

 Good Day,

  

 Mark Napier

  

    

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akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Fri Aug 24, 2007 7:03 pm Post subject: Re: 582 engine adjustments

We are running two 582's here with clutches..no problems on idle.  It has to be a carb adjustment, or a leaky seal I would think.  Have you had a leak check done?

msm_9949(at)yahoo.com
Guest

Posted: Mon Aug 27, 2007 11:55 am Post subject: 582 engine adjustments

Thanks Mark. I'll try that.

   

  do not archive.



"Napier, Mark" <Mark.Napier(at)sciatl.com> wrote:

  [quote]      I had one more brain cell fire while driving home.  I remembered listening to Tom Olenik on the ultraflightradio archives.  He said that in the early days they had a hard time getting the engines to idle.  One fix was to cut a rectangular slot in the back of the slides to let more air through.  The idea was to allow more charge into the cylinders at idle to compensate for the loading of the prop.  These carbs came from motorcycles engines that don't have a prop hanging on them at idle.  Now all the Bing carbs for  Rotax aircraft engines come with slides that have a slot in the rear.  

   

  But now with the clutch, he had to file on the bottoms of the slides to get less air into the engine at idle; basically trying to undo the slot at the rear of the slide.  Your trying to get the engine to idle at 1800 rpm or less with no load and that's much less power (fuel air mix) than the carb is currently set up for.

   

  You might ask one of the companies that sell the clutch how they set up their engines.

   

  Good Day,

   

  Mark Napier

  on Yahoo! Travel.  [quote][b]

Jeffrey Dill

Joined: 23 Jul 2007
Posts: 52
Location: Pleasant view, TN

Posted: Tue Aug 28, 2007 5:10 am Post subject: Re: 582 engine adjustments

Mark, Thanks for your input regarding 582 adjustment. Too much good info there for me to respond intelligently. You seem to know carburetion at a level I envy and need to catch up to. Two things in the chatter caught my attention:



4 turns is the effective range for the low jet. Other sources online suggested only 2 1/2 turns were effective, so, when backing it out looking for smooth operation below 4000 RPM,  I stopped there. Idle jets are running $32 each, plus shipping, I assume. It would be worth $70 bucks to get rid of this 4 cycling, which has to leave me at risk for secondary vibration damage, but as somebody already observed, my problem sounds like the midrange jet. I see a succession of throwing parts at it in a hit or miss fashion. If I buy new idle jets, I guess I would go straight for the #45.

In my ignorance, I have to defer to the local guidance, but I think he might be wrong. He does not want me to move the mid range jet needle setting. (The needle is 11G2 I operate at sea level on the third notch)  This is because of his fear of running too lean. When we tried it once, briefly, on notch 2 instead of 3, he looked at the spark plugs and concluded that it was running too hot, so we put it back to the third notch. I was running the engine during static test and recall the EGT to be around 1050. He is a motorcycle guy and the EGT meant nothing to him. So, who is right?  Am I going to burn a hole in my piston with that EGT or not? Or, am I not asking the right question, am I going to burn a hole in my piston with a hot looking spark plug? Why should I buy all this hardware to allow me to lean my engine when I can't even move what I have to a leaner setting? Thus my dilemma, which I will continue to sleep on. Just typing it out is therapeutic.

The discussion about clutch disengagement was news to me as well. I have north of 14000 hours and 30 years of flying, and I feel like a complete idiot.  I am assuming it is a feature of a different gearbox? I have a B box.

_________________
Jeff Dill
Model 2

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Tue Aug 28, 2007 7:41 am Post subject: Re: 582 engine adjustments

The clutch is only available for the C gear box.. but is is one heck of an upgrade.  A nice SMOOTH idle even when cold.  The plane does not try to move during warm up on floats.. the list goes on and on..



No need to feel like an idiot.  This is a whole new ball game for you and the only dumb question is the one that you dont ask... and that is usually the one that leaves you stuck in the trees at the end of the runway lol....



If the EGTs were 1050 then I would say you were where you need to be.  did you take it around the patch?  1050 to 1100 is what you are looking for.

Mark.Napier(at)sciatl.com
Guest

Posted: Tue Aug 28, 2007 7:48 am Post subject: 582 engine adjustments

I wouldn't say my knowledge is all that great -> limited to my engine on

my plane only.



Also, your mechanic friend is right.  If you can stop the engine and

read the plugs that is a good way to verify the mixture.  But, how do

you do that?  The only mixture that really counts is the one where the

prop unloads in the air and you pull the throttle back.  You would have

to kill the motor under those conditions over the field, get the prop to

stop freewheeling so it doesn't drive the motor, dead stick land, and

then read the plugs.  No thank you.



Also, he is right that the EGT's are only exact if the probes are the

correct distance from the exhaust port, the probes are new, and the

outside temperature is 70 degrees.  Otherwise you have to use them as

advisory.  The Westach web site tells a good deal about these gauges.



Interestingly, I've talked with a couple of guys at Mountain Airpark who

run 582's on 2-place single sail ultralights that are very draggy.  They

run the stock jetting and the EGT's don't vary much at all.  The only

thing I can figure is that the engines don't unload much in the air due

to the draggy airframes and the props are very flat to produce thrust at

low speed.



Think of it this way:  the engine is a pump for air.  At a given RPM it

will pump through about the same amount of air with some variation due

to pressure (vacuum) from the throttle setting but the main driver is

simply RPM.  However, the slide carb changes the amount of gas delivered

mainly based on the slide position.  Again, there is some variation due

to the amount of air (venturi vacuum) pulled through the carb by the

engine (RPM) but the main control is the slide position.  The engine RPM

is controlled by the amount of charge in the cylinders (torque) and the

load imposed by the prop.



So increase the load, the engine slows down and pumps less air, the carb

still supplies gas at a rate governed by the throttle setting so the

mixture gets rich.  Decrease the load and the engine speeds up and the

opposite happens.  Point the nose down at cruise and pull the throttle

back to produce less power.  The RPM remains about the same because of

the reduced load.  The decreased pressure does reduce the power and the

prop load is also reduced but the slide position greatly leans the

mixture and the EGT's rise.  Some less air but much less gas.



So anyway, I would just keep trying things one at a time.  Don't let

your EGT's go over 1200 degrees in the air or you will toast the rings,

1100 is a good target.  The prop pitch is the #1 mixture control.  High

pitch means the engine will run hot (water temp -> producing power) but

the EGT's will be low (running rich).  Low pitch gives you the opposite.

My GSC prop is pitched to where it will only do about 5900 on the ground

so my engine runs rich.



Yeah, $70 a pop for mixture changes stinks but so does having the plugs

foul up and the engine quit on final.  Mine did that several times

before I got the idle right.  I took to coming in high with power and

standing on the rudder to slip down to a landing.  The habit remains.

It does help to keep the water temps up in cool weather.



I did that one day when it was windy and got batted around a good deal

coming down.  Then off came cowling to poke around inside.  While I was

doing that a police car come up.  Someone had reported a plane coming

down in distress and he was looking for the accident.  Humm.  Guess if

my approach and landing can't be distinguished from a crash in progress

by the casual observer I should work on my technique a little more.



:^)



Cheers,



Mark Napier



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Jeffrey Dill

Joined: 23 Jul 2007
Posts: 52
Location: Pleasant view, TN

Posted: Tue Aug 28, 2007 8:24 am Post subject: Re: 582 engine adjustments

I will play with it again tomorrow, hopefully. But I will say this. Due to a Tach out of whack, I was originally turning only 5500 static. Now that I have it tuned for 6200, the EGTs have come up from around 950 to around 1050. Last time I flew, I looked for an EGT rise in an idle descent (didn't know to watch out for it before that). I did not see any tendancy for them to rise toward 1200. I never really saw above 1050. I might take that to indicate that I still have room to make the mixture leaner, namely move the jet needle  to #2 slot.

_________________
Jeff Dill
Model 2

Mark.Napier(at)sciatl.com
Guest

Posted: Tue Aug 28, 2007 9:52 am Post subject: 582 engine adjustments

Hey Jeff,



I didn't answer your main questions.  By raising the needle I mean lower

the clip to the next available notch to enrich the mid-range.  Your guy

is probably right that moving the clip to the 2nd notch will run the

motor too lean esp. in the air where it counts.



If you put in a leaner idle jet your lower midrange will be leaner as

well.  If you raise the needle (by lowering the clip) that will make

your idle a little richer so that you will need a leaner idle jet.



Going to a larger needle jet enriches the mixture across the entire

mid-range.  Raising the needle mostly enriches it at the lower end.  The

main jet sets the full-throttle mixture and affects the high-end of the

mid-range.



Regarding the air-bypass screw, you can only back it out a few turns

before the o-ring starts showing and then the darn thing will vibrate

out.  There's no adjustment left so you have to go to the next leaner

jet.



1050 is probably OK during static run up but I hate to say because I

don't know anything about your prop, how it is pitched, what RPM your

static is, how draggy your plane is, how accurate the measurement is

etc.  For the 1st flight you can be a little rich on the main jet as

long as you are making good power.  You'll just have to make your best

guess on the ground and fly it to see.



That clutch is an aftermarket option on the C gearbox.  One guy here had

one on his ultralight.  He could cut the motor and land *very* short.

The reason is that he could get the engine to disengage at idle in the

air and then the prop would spool up like a windmill and add tremendous

drag.  I don't want that on my plane.  An engine out would be

interesting enough already.



BTW, my idle is set up so that it is around 2000 on the ground and

pretty stable but I don't run it there because of the gear lash.  I

usually warm up and motor around in the grass at around 3000.  But on

landing you want that low power setting so you don't "float" down the

runway.  Because of the reduced load it is still be turning ~2400 until

I touch down.



14000 hours?  Wow.  I've only got around 320 with 200 in this little

bird.  Pretty funny flying into Asheville with all the big corporate

jets.  Sunday I went in and there was a military jet trainer holding

short waiting for me to land so they could take off.  No, I didn't stop

on the runway but the Kitfox is so slow that even flying down to the

exit to land I'm sure it looked that way to them.

Cheers,



Mark Napier

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proprietary, privileged or otherwise protected by law. The information is solely 

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