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pj.ladd(at)btinternet.com
Guest

Posted: Fri Jun 19, 2009 1:21 am Post subject: Rotax 503 running problem

So I just tow the line on what we know to be the most reliable running 

configuration, rpms, installation, etc. and fly instead....>>



Hi Lucien,

I agree except that I would `toe the line` not `tow the line` Heh Heh. 

Theres another controversial thread!



Cheers



Pat

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Fri Jun 19, 2009 2:55 am Post subject: Rotax 503 running problem

At 10:08 PM 6/18/2009, dalewhelan wrote:



 	  Quote: 	
		  Not that this was the intent of this thread but, Is there anyone on this 

board other than myself that has tried running more than the 

recommended  amount of oil and willing to share with me what they found.

Just for fun, even though I have no inclination to do so, is there anyone 

on this board that has run less oil than 50:1, ( I once saw a company 

claim you could run their oil at 150:1) If so would you share your results 

with me?


	


I have not, but kart and bike racers sometimes fiddle with the oil mix to 

adjust the mixture when there's no time to make a jetting change (more oil 

= less fuel so the engine runs leaner, and vice versa).



Remember that the oil lubricates, but it's the fuel, not the oil, that 

cools the engine.  More oil may give you more lubrication, but it's a much 

worse at taking away heat than fuel.  Also too much oil and you start 

fouling spark plugs, particularly at low power settings... your engine may 

quit (or just hesitate) just when you need it most, to go around or simply 

stretch your glide after a long descent.  Not to mention gunking up the 

rings, and the black gook coating your prop.



OTOH, I have people telling me I should run my Cuyunna at 50:1 rather than 

the manufacturer recommended 40:1... but I can't see any advantage.  Sure, 

I'd spend a bit less on oil, but it runs fine as it is, and I don't foul 

plugs, so why mess with a good thing and have to fiddle with jetting all 

over again?



-Dana

--

  The sex was so good that even the neighbors had a cigarette.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Jun 19, 2009 4:50 am Post subject: Rotax 503 running problem

> We just need to be careful.

 	  Quote: 	
		   Some people have been kind enough to share some things with me off list, 

 they make some good points. They even gave me reasons for why it could be 

 bad and what to watch for.

 > Dale Whelan
	




In the world of aviation we're looking for reliability while working with 

continuous duty engines that are more like tractor and equipment engines 

than racing engines.



I have found that the engineers at Rotax are pretty smart guys.  They do a 

good job of setting up the engines when they leave the factory.  The primary 

problem encountered by most enthusiast is correct prop pitch/loading.  If it 

is correct, jetting and spark plugs that come in the engine from the factory 

will also be correct.  The only other factor that will change factory tuning 

is altitude and temperature extremes, if you are running the correct fuel 

and oil.



To match the engine and prop is pretty simple.  I have found if I pitch the 

prop to just bump the red line at wide open throttle (WOT), straight and 

level flight when the airplane is flying as fast as it is going to fly, I 

have loaded the engine correctly and I will get the best performance in 

climb and cruise.  EGT and CHT will also be in the green.



The biggest mistake aviators make with two stroke engines is trying to tune 

a two stroke to a prop that is not properly loading the engine.  Once they 

start this, they start chasing their tail in a circle that either never ends 

or ends when the engine seizes.



Somewhere along the line I remember, either a Shell engineer or during one 

of Eric Tucker's Rotax engine courses, that operating with too much oil is 

detrimental to Rotax two strokes in many ways.  One way is crank shaft 

bearings which are designed to operate at a certain level of oil in the 

crank case.  Too much oil can cause these crank shaft bearings to fail. 

Next time I talk to Ronnie Smith or Eric Tucker I will try to remember to 

ask them about this.  May be a figment of my imagination, but I don't think 

so.



I don't get involved with two stroke aviation much any more.  I haven't seen 

much change in them in the last 25 years that I have been involved in 

ultralight and light plane aviation.  My experience was to follow the book, 

leave them alone the way they came from the factory, fly them hard and not 

baby them.  I had good luck and flew two strokes over a lot of this country 

back in the old days.  I was not interested in squeezing every ounce of 

power out of the little engine or changing what the factory engineers had 

written in the operators manual.  My primary goal was to get there and get 

home safely, and have a lot of fun while I was at it.



The environment we play in is very unforgiving.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Fri Jun 19, 2009 5:04 am Post subject: Re: Rotax 503 running problem

 	  pj.ladd(at)btinternet.com wrote: 	
		  

Hi Lucien,

I agree except that I would `toe the line` not `tow the line` Heh Heh. 

Theres another controversial thread!



Cheers



Pat 	




Heh. I stand corrected. 

No more controversial threads for me, as I'm not into online group therapy anymore. If people get flustered upon presentation of the facts, that's their problem and I'm outta there. 



LS

_________________
LS
Titan II SS

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Fri Jun 19, 2009 5:36 am Post subject: Re: Rotax 503 running problem

 	  John Hauck wrote: 	
		  

Somewhere along the line I remember, either a Shell engineer or during one 

of Eric Tucker's Rotax engine courses, that operating with too much oil is 

detrimental to Rotax two strokes in many ways.  One way is crank shaft 

bearings which are designed to operate at a certain level of oil in the 

crank case.  Too much oil can cause these crank shaft bearings to fail. 	




Another problem is the Dykes rings used in our 2-strokes. The longevity and maintenance schedule for these engines was very carefully arrived at at _only_ the suggested oil mixture of 50:1 (premix). 



Normally, a Dykes does it's own decarb of the ring land as it moves in and out of the ring groove during operation. With too much oil, however, this can be interfered with causing premature sticking of this ring with the obvious disastrous results.



Usually it's the lower ring that starts to stick first and this was the original reason for the suggested 50 hour decarb schedule by Rotax. With the correct oil mix, however, we can go 150 or more reliably before having to do a teardown and decarb, generally because the Dykes continues to seal normally.



With too much oil, you're putting yourself in unknown, and thus very dangerous, territory here not to mention all the other problems associated with doing that.



In fact, even 50:1 is a little too much oil at lower rpm and power settings, which is why the Rotax oil injection is preferred over 50:1 premix. It leans the oil mix out to closer to 70:1 at reduced throttle settings - ring sticking/general coking is even further reduced with the oil injection and you can sometimes go as long as 300 hours without having to do a decarb (with regular inspections of the rings thru the exhaust ports of course).



Motorcycle experience does NOT translate automatically to safe advice on a 2-stroke on an _airplane_. The applications are _different_ and we have to be very careful about where we get our advice on this like I said.



It's unfortunate that some had to get all riled up at being corrected on this. For that personal issue I suggest going to a good friend, relative, pastor etc. for solace and or guidance. That's not my problem. 



Keeping someone's airplane out of the dirt or worse when I can help with that, tho, I'll go ahead and ruffle feathers if I have to, referring the upset parties to someone else for comfort for their issues. I'd rather we all be able to swallow our pride and keep flying instead of spending our money on parts for the plane, lawsuits with insurance co's and visits back and forth from the guys at the local FSDO. It's a pretty fair exchange for a little humility if you ask me. 



The excessive oil use thing is one of these. Let's be careful out there guys.



LS

_________________
LS
Titan II SS

Last edited by lucien on Fri Jun 19, 2009 6:22 am; edited 2 times in total

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Jun 19, 2009 5:54 am Post subject: Rotax 503 running problem

---

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Jun 19, 2009 6:23 am Post subject: Rotax 503 running problem

>we have to be very careful about where we get our advice on this like I 

said.

 > LS

 	  Quote: 	
		   Titan II SS


	


I'll agree with the above.  Most of us, on this List, are known only from 

what we post, not what we have actually done and do.



john h

mkIII - 2,950+ hours

912ULS - 389 hours

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Fri Jun 19, 2009 6:49 am Post subject: Re: Rotax 503 running problem

 	  John Hauck wrote: 	
		  

I'll agree with the above.  Most of us, on this List, are known only from 

what we post, not what we have actually done and do.



john h

mkIII - 2,950+ hours

912ULS - 389 hours 	




Absolutely, 100% correct. 



In fact, for the 2-stroke experience I've given here, it's easy to verify independently. If anyone is so inclined, one of the best resources is Mark Smith at tristate kite sales (www.trikite.com). He's the most experienced repairman and operator of the Rotax 2-stroke line of engines in the US and probably the whole world.  He started flying/maintaining 2-strokes, Rotax and others, in the late 70's and is still flying and working on them regularly today. 



He'll give you the right scoop on the 503.



I've followed his advice on them religiously and sure enough accumulated about 10 years of great flying under/in front of the 447 and 503's with only one engine out with the 447 (wiring error on my part) and not so much as a hiccup out of the 503.



So again noone has to believe me, and in fact I'd be smart not to take my experience at face value anyway.  There're lots of other resources to draw from to confirm my experience.



LS

_________________
LS
Titan II SS

pj.ladd(at)btinternet.com
Guest

Posted: Fri Jun 19, 2009 7:12 am Post subject: Rotax 503 running problem

online group therapy>>  I like that



Cheers



Pat

dalewhelan

Joined: 11 Nov 2008
Posts: 105
Location: USA ARIZONA fountain hills

Posted: Fri Jun 19, 2009 9:24 am Post subject: Re: Rotax 503 running problem

I like the direction this thread has started to move in.

Because I told you so has never been reason enough for me.

I prefer to understand why.

_________________
Dale Whelan
503 powered Firestar II, Luscombe 8A
Projection, A simple and interesting Psychological concept

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Jun 19, 2009 9:53 am Post subject: Rotax 503 running problem

> I like the direction this thread has started to move in.

 	  Quote: 	
		   Because I told you so has never been reason enough for me.

 I prefer to understand why.



 --------

 Dale Whelan


	




Experience is not gained behind the keyboard and monitor unless you are 

striving to improve your computer skills.



john h

mkIII - Loaded up and on the way to see Brother Jim in Woodville, FL.  Not 

flying this trip, but pulling the 5th wheel at 70 mph, hopefully.

            Haven't had a chance to improve my flying experience since I 

landed from my flight out West three weeks ago today.  Gosh, seems like 6 

months.

            I'm ready to go again.

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

captainron1(at)cox.net
Guest

Posted: Fri Jun 19, 2009 3:39 pm Post subject: Rotax 503 running problem

I am listening attentively here. I will be flying in short order a cayuna 430 which is running good now on 35-40 to 1 mixture. sort bounced around in the Ultrlight this morning. I will need to put about 6 hours without any stoppages to satisfy a deal for some survey work. The advice I am getting here is to remain on 40/1 mixture that Cayuna recommended. 



I guess I'll stick with that. Is there anything none exotic that I can get at Walmart that will do the job, or do I need to get some special oil. I think I read in the past that Pennzoil something or other is the recommended oil, is that so?



Ron (at) KFHU



======================== 

---- lucien <lstavenhagen(at)hotmail.com> wrote: 



=============


John Hauck wrote:

 	  Quote: 	
		   

 

 

 I'll agree with the above.  Most of us, on this List, are known only from 

 what we post, not what we have actually done and do.

 

 john h

 mkIII - 2,950+ hours

 912ULS - 389 hours


	




Absolutely, 100% correct. 



In fact, for the 2-stroke experience I've given here, it's easy to verify independently. If anyone is so inclined, one of the best resources is Mark Smith at tristate kite sales (www.trikite.com). He's the most experienced repairman and operator of the Rotax 2-stroke line of engines in the US and probably the whole world.  He started flying/maintaining 2-strokes, Rotax and others, in the late 70's and is still flying and working on them regularly today. 



He'll give you the right scoop on the 503.



I've followed his advice on them religiously and sure enough accumulated about 10 years of great flying under/in front of the 447 and 503's with only one engine out with the 447 (wiring error on my part) and not so much as a hiccup out of the 503.



So again noone has to believe me, and in fact I'd be smart not to take my experience at face value anyway.  There're lots of other resources to draw from to confirm my experience.



LS



--------

LS

Titan II SS





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p 49103#249103



--

kugelair.com

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Fri Jun 19, 2009 5:18 pm Post subject: Rotax 503 running problem

Try putting five gallons of diesel in it sometime.

I did that once when I used the wrong "green" handle at

the gas station where they have both gas & diesel

at the same pump and I had a hangover. Of course I had already added the

requisite amount of oil to the can so .............. don't know

what mixture that might have been.



The sucker started and smoked like a mosquito fogger. But it ran.

I finally figured out what I had done after about five minutes

of smoking up half the county. I actually think it

helped lube up the bearings, but you could never rev it up

high enough to take off.





 	  Quote: 	
		  



To oil ratio I think giving it a bit more oil will improve its 

reliability. I guess you can wonder if there is any point to it, to 

make more smoke and less power. Once you reach the point where the 

motor gets all the lube it needs then we ain't doing it anymore good 

tossing more oil into it.

We just need to be careful.



Ron (at) KFHU

-============================================================

_________________
Possum

captainron1(at)cox.net
Guest

Posted: Fri Jun 19, 2009 7:35 pm Post subject: Rotax 503 running problem

Thanks for the laugh.   



Ron (at) KFHU



==================

---- possums <possums(at)bellsouth.net> wrote: 



=============




Try putting five gallons of diesel in it sometime.

I did that once when I used the wrong "green" handle at

the gas station where they have both gas & diesel

at the same pump and I had a hangover. Of course I had already added the

requisite amount of oil to the can so .............. don't know

what mixture that might have been.



The sucker started and smoked like a mosquito fogger. But it ran.

I finally figured out what I had done after about five minutes

of smoking up half the county. I actually think it

helped lube up the bearings, but you could never rev it up

high enough to take off.





 	  Quote: 	
		  



To oil ratio I think giving it a bit more oil will improve its 

reliability. I guess you can wonder if there is any point to it, to 

make more smoke and less power. Once you reach the point where the 

motor gets all the lube it needs then we ain't doing it anymore good 

tossing more oil into it.

We just need to be careful.



Ron (at) KFHU

-============================================================


	




--

kugelair.com

sky-king(at)inbox.com
Guest

Posted: Sat Jun 20, 2009 6:51 am Post subject: Rotax 503 running problem

Sounds like you had plenty of lubrication.LOL I have found that in this world,we should learn from other peoples mistakes,most safety rules are put in place because someone else has been hurt or killed.If you play bt the rules than most of the time you will be fine.BTW "can't we all just get along"



[quote] --

dalewhelan

Joined: 11 Nov 2008
Posts: 105
Location: USA ARIZONA fountain hills

Posted: Sat Jun 20, 2009 8:35 am Post subject: Re: Rotax 503 running problem

[quote="John Hauck"]> I like the direction this thread has started to move in.

 	  Quote: 	
		   Because I told you so has never been reason enough for me.

 I prefer to understand why.



 --------

 Dale Whelan



	




Experience is not gained behind the keyboard and monitor unless you are 

striving to improve your computer skills.



I am sorry but I am not sure what you are trying to say.

You quoted me but I don't see the continuity to your response.

Just to clear the air I am not riled up and on a scale of 1 to 10 the most I have been on this board is about 1.5.

I can question people without being riled up.

Are you saying the only place to improve my flying skills is flying my plane?

Are you saying you are tired of hearing from me?

Did I completely miss what you were trying to say?

Just trying to understand.

_________________
Dale Whelan
503 powered Firestar II, Luscombe 8A
Projection, A simple and interesting Psychological concept

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Jun 20, 2009 10:40 am Post subject: Rotax 503 running problem

> You quoted me but I don't see the continuity to your response. 

 	  Quote: 	
		   --------

 Dale Whelan

 
	




Dale:



My screw up.  Was not intended to reference your post.



Sorry about that.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

mshimei(at)bellsouth.net
Guest

Posted: Sun Jun 21, 2009 8:05 pm Post subject: Rotax 503 running problem

Not that this was the intent of this thread but, Is there anyone  on this board 

other than myself that has tried running more than the  recommended amount of 

oil and willing to share with me what they found. 

Just for fun, even though I have no inclination to do so, is  there anyone on this 

board that has run less oil than 50:1, ( I once saw a company  claim you could 

run their oil at 150:1) If so would you share your results with  me? 

-------- 

Dale Whelan 

503 powered Firestar II 

I had a Phantom with a  Kawasaki 440....got some "advice" from J-Bird......He claimed it needed to be  mixed at 20:1 or it will burn up. 

So I  did. 

In 30 hours the rings  had so much carbon packed in them it pushed them out into the ports,,,not a good  thing.Landed (glided)on the airfield,took it apart and was surprised at what was  in there.Carbon in the ports,exhaust,etc.I also found my gauges were not  very accurate..replaced them. 

Got another used  engine with 100+ hours on it,mixed 50:1,,,,,Havoline or Penzoil,,,,and put 260  hours on that one and then sold the plane.No problems with fouling,ring  sticking,etc.and never de-carboned it.Ran the same from the day I installed  it,to when I last flew it. 

My friend flew his  SE-5A with a Cuyuna for over 300 hours,50:1,Amsoil 2 stroke.Replaced it with  something else when it just quit running.Think it was a gearbox  problem. 

Mark ..Ultrastar,  UL2    26 hrs 

 

   [quote][b]

dalewhelan

Joined: 11 Nov 2008
Posts: 105
Location: USA ARIZONA fountain hills

Posted: Mon Jun 29, 2009 9:45 pm Post subject: Re: Rotax 503 running problem

Back to the original question about the bad running 503

My buddy did check the pulse generators and found one of them to be mounted in a completely retarded position compared to the other.

I will set the timing with my dial indicator.

This should solve the different speeds with the different Mags.

Have yet to find the cause of the overall Rpm Drop.

I may get to look at it this weekend.

I will let you know if I find the answer.

_________________
Dale Whelan
503 powered Firestar II, Luscombe 8A
Projection, A simple and interesting Psychological concept

R. Hankins

Joined: 18 Jan 2006
Posts: 185
Location: Grants Pass, Oregon

Posted: Tue Jun 30, 2009 12:00 am Post subject: Re: Rotax 503 running problem

Dale:

The 503 is the workhorse 2-stroke of the ultralight world.  They are known for their ease of operation, long life, and reliability. 

I don't think you will find a whole lot of active pilots (especially those who often fly over harsh terrain) who are willing to risk their health and their airplane by running the 503 outside of long proven parameters. 



I have never experienced so much as a hiccup from my 503.  I decarboned it at 119 hrs, changed oil brands and ran it to 450hrs.  At that point I tore it down and replaced every moving part because I happened to have the time and money, not because the engine was showing signs of being tired.  I measured everything.  The only component that was outside wear limits was a small portion of the cylinder bore, just above the intake port.  Even that was less than 0.001" oversize.  I probably could have gotten another couple hundred hours out of it.  The thing is, after spending several years building an airplane, one doesn't really want to find where the failure point of the engine is. I figured 150% of TBO was good enough.



There are many, many 503s out there that have flown past 1000hrs without an overhaul, and literally thousands that have flown to twice TBO.  Very few actually get rebuilt at 300hrs.  I guess what I'm getting at is what do you stand to "gain" by adding more oil?  It seems you are trying to solve some perceived "problem" with the 503 that simply doesn't exist.  This is probably why Lucian questioned your experience.  He wasn't saying you don't know your way around engines in general, he was asking about the 503 in particular because anyone who has much time flying them knows they are one of the most reliable two-strokes out there.



My first response when reading your post was "You're running 32:1? , Why?" This is a great little engine that performs very well.  All you have to do is feed it right and keep the gauges in the green.   Treat it kindly and it will return the favor.

_________________
Roger in Oregon
1992 KXP 503 - N1782C

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