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DL 50 low compressions, low power, bad idle

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DL 50 low compressions, low power, bad idle

Old 07-30-2009, 04:13 PM
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Tired Old Man
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Default RE: DL 50 low compressions, low power, bad idle

Every time I talk to you you're talking about eating beans and hot dogs. I was under the impression you liked them Must be the effects of all that free prop drilling

Cambo,

I'll be back where the rings are Monday. We can go from there. I'm with Jody on the compression issue. If you don't immediately see a change in compression after reassembling the engine with a new ring I would not run it. Some may feel that not running the ring in first is a bad idea but if you had a ring with bad tension it would show up immediately. If you have a cylinder issue there's no reason to match a new ring to it.
Old 07-30-2009, 05:25 PM
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Default RE: DL 50 low compressions, low power, bad idle

T.O.M
Sounds good, let me know when you are back

f5air, the oil is echo 2 stroke aircooled

Cameron
Old 07-30-2009, 06:16 PM
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Default RE: DL 50 low compressions, low power, bad idle


ORIGINAL: Cambo


f5air, the oil is echo 2 stroke aircooled

Cameron
And I would have bet it was LawnBoy, I'm striking out today.[:@]
Old 07-30-2009, 06:27 PM
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Default RE: DL 50 low compressions, low power, bad idle

May I ask at what ratio and was the engine deliberately run rich for a break in? The reasons are too much oil and too rich carb settings will not let an engine become warm enough to execute the break in. A "cold" engine does not generate the required wear on a ring and cylinder to perform a break in. As you can see in the 500 hour photo, pistons should not wear for the most part. Perhaps a little scuffing on the lower skirt but nowhere else. The ring is what makes all the contact with the cylinder, and even then will ride on a thin film of oil when everything is working correctly.

For general knowledge, an engine will not effectively atomize the fuel entering the carb and case until the engine attains roughly 90c, or 194f. Up to that point what is essentially a river of cold fuel is being poured into the engine. After 90c the fuel starts to be effectively atomized. Even then it's not as well done as it could be. The entire engine with all it's components needs to "heat soak" for the best fuel atomization and use. That takes place when the engine attains temps somewhere between 120 and 140c and the pumping action of the case and porting becomes much more effective. Above 148c the engine starts to lose performance but does not sustain any negative effects until past roughly 170c. There are exceptions to those numbers but those exceptions are not applicable to small gasoline fueled air cooled engines. Can't go any farther with that...

So an engine needs to be heat cycled though it's normal operating temperature range for a break in. Warm up, cool down, and repeat for several gallons of gas. A few hours really. That's where some that do bench running make some big mistakes, while others that go out and fly hard 3d with a brand new engine make even more. Normal flying with carb mixtures suitable for the best performance are what wioll break in an engine faster and more effectively than any other method.
Old 07-30-2009, 06:33 PM
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Default RE: DL 50 low compressions, low power, bad idle

I have a thought that might be helpful for you Cambo. I notice you're in Phoenix. What's he possibility of you making an hour and a half drive up to Williams, AZ? If you have that ability it would be well worth your time and a box of good cookies to call Ralph Cunningham of RC Ignitions and see if you could come visit. You would learn much and he would be able to take a look at your engine and set anything straight.

He's a real good guy and prolly would not mind the company. You'd have to deal with a lot of phone interruptions but you would not be sorry for the trip.
Old 07-30-2009, 07:01 PM
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Default RE: DL 50 low compressions, low power, bad idle

Now you're sending my potential labor revenue away, what did Ido to you?Andplease reset your thermometer to F, yourin the USAfor crying out loud.

Hope you're enjoying your time at home.
Old 07-30-2009, 07:49 PM
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Default RE: DL 50 low compressions, low power, bad idle


ORIGINAL: soarrich

And I would have bet it was LawnBoy, I'm striking out today.[:@]
While I'm no LawnBoy oil supporter, I think many people bash it unnecessarily! Case in point ..... several of my older engines came to me from a very good friend who, shall we say retired from the hobby because he was fortunate enough to get too old to enjoy flying any more. Now he watches someone else fly his fleet of airplanes. He was a loyal LawnBoy oil user and at fairly high mix rates .... my guess 25:1 to 30:1. The internals of his engines look as good as the piston Tired Old Man posted the picture from and many of his engines are fairly high time engines. Very little piston dome or combustion chamber carbon, very little to almost no blow-by produced piston skirt staining, etc. I can never remember him having a bearing problem of any kind in any of his engines. Now the mufflers and exhaust ports are another matter as LawnBoy oil is known to carbon up these areas ... even in the mowers. But the lubrication of the internal parts just can't be questioned .... at least for this small fleet of engines. FYI, the engines include several examples of Zenoah, FPE, DA, Quadra, etc. so many different brands are represented.

Sometimes I wonder if some people bash LawnBoy just because it is the popular thing to do. I don't use it because I don't want to have to clean out my mufflers every few years and for another reason few ever mention ..... it is expensive! Just my $.02 worth on the subject.

My bet regarding the DL in question on this thread is that it was probably run cold and rich as TOM stated. I doubt that oil choice had much to do with the nasty appearance of the internals. Of course, the ring or cylinder might have been less than round also. All hard to tell from just viewing a few pictures.
Old 07-30-2009, 09:33 PM
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Default RE: DL 50 low compressions, low power, bad idle

Idon't "bash" any brand of anything. I'm lucky enough to get to see the inside of a LOT of different engines, most of themwith some kind of problem. I ask questions as to how the engines are used and cared for and I take notes as to the condition, appearance and what the engines have been ingesting.My commentsregarding Lawnboyoil are based on factfrom use in model aircraft engines only.

If you like gooey carbon build upin yourcombustion chamber, on the top of your piston, stuck rings, reduced exhaust port area and volume, plugged up mufflers, fouled spark plugs, and black crap down the bottom of your airplane then you can't gowrong withLawnboy oil. If you wantall that to happenas fast as possible, just run it rich like you would a glow engine.
Old 07-30-2009, 09:48 PM
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Default RE: DL 50 low compressions, low power, bad idle


ORIGINAL: jedijody

I don't ''bash'' any brand of anything. I'm lucky enough to get to see the inside of a LOT of different engines, most of them with some kind of problem. I ask questions as to how the engines are used and cared for and I take notes as to the condition, appearance and what the engines have been ingesting. My comments regarding Lawnboy oil are based on fact from use in model aircraft engines only.

If you like gooey carbon build up in your combustion chamber, on the top of your piston, stuck rings, reduced exhaust port area and volume, plugged up mufflers, fouled spark plugs, and black crap down the bottom of your airplane then you can't go wrong with Lawnboy oil. If you want all that to happen as fast as possible, just run it rich like you would a glow engine.
A couple of the mentioned engines have not been run since their LawnBoy diet. I should send them to you for inspection. You will find excessive exhaust port carbon but thats it .... pistons and cylinders are nice and clean, etc. Of course, they were adjusted properly throughout their life and that may have made a difference. The balance of the engines as well as my newer personal engines are now run on Pennzoil which as many suggest, seems to be the best compromise as far as oils are concerned. By the way, we never had excessive black crap on the bottoms of the airplanes with LB, even at high oil ratios.
Old 07-30-2009, 09:55 PM
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Default RE: DL 50 low compressions, low power, bad idle

Well, i do have a few confessions to make. First and foremost, this was my first gas engine. I went out and bought a 2 gallon can when i purchased the engine and made my first mistake. I put 2$ not 2 gallons in. DAAAA. And then mixed at 32:1 for 2 gallons. This was when gasoline was 4 bucks a gallon. So i was already off to a bad start. I didn't run that for long, it was only about 5 flights before i realized it, but that was still most of the over oiled fuel. I flew it gently, powered up lines with low-powered downlines. The problem i made is over trusting the stock needle settings. The factory settings had my engine running WAY rich on the low end in the air. Being on a plane that weighs 16 pounds fueled, i stayed away from high throttle settings. So the engine sputtered in the air, but never died, and transition well so it didn't bother me much. It smoothed out so much upside down that i didn't want to over lean the low end, i felt that it might die. Turned out i was wrong. About two weeks ago i tuned the engine while it was running and got the low end SOOOO smooth. The spark plug, after only one flight, looks the way it should. I have gone through 2, both totally carbon fouled. I just never took the hints.

That being said i cleaned out the engine fallowing T.O.M's instructions, pics are below. Note, the black stuff around the cylinder is not carbon buildup but gasket material.

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Old 07-30-2009, 10:35 PM
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Default RE: DL 50 low compressions, low power, bad idle

Can we see a close up of the ring? Specifically the edge of the ring on both sides? A close shot or two of the inside of the cylinder? That one can be tough. Have to shoot a lot of pics to get a couple that depict well. I'm starting to think there may be nothing at all wrong with your engine.
Old 07-30-2009, 10:47 PM
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Default RE: DL 50 low compressions, low power, bad idle

that cleaned up nicely. I have a dl 50 also, power is always good, I can get the high end running really nice ~6700-6800 rpms consistently, but the low end I can't get right at all. The throttle arm will not go back any further than what it does, which at a good transition tuning gives the thing between 2000-2500 rpm depending on the day. but in order to lower the idle enough to land without having to kill the engine to make the plane come down, I have to make the low end so rich that the transition is horrible. That kinda bothers me cause i like my plane, for a while it wouldn't take throttle at all, but I found that to be the little micro screen in the carb was caked in crud. I read earlier about timing...anyone think that could be the problem here?
Old 07-30-2009, 11:07 PM
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Default RE: DL 50 low compressions, low power, bad idle

Timing is most likely not the problem. It always amazes me to here of all the different running quality problems that some people put up with then maladjust their engine to compensate for an obvious deficiency.

msuviper68, you most likely have either some kind of mechanical problem with the thottle valve or an air leak of some kind, possibly both. No matter where the needles are set at, the engine should die if the throttle valveis pulled all the way closed.

Cambo, Well done, that looks very good and TOMmay beright, you may not have anything wrong at all.
Old 07-30-2009, 11:11 PM
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Default RE: DL 50 low compressions, low power, bad idle

Okay, the cylinder ones didn't come through as well as i hoped.

TOM, can you explain your theory, I certainly hope you are correct.
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Old 07-30-2009, 11:14 PM
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Default RE: DL 50 low compressions, low power, bad idle

thats what I had first thought too. Trust me, I'm not a dumbass and just adjust to compensate for laziness. I have checked for airleaks, and also checked the throttle (many times), and have found nothing wrong. I've also had others look at it and check it, they came up with nothing also. This after replacing gaskets to see if that was a problem also. The engine was originally on a CAP, and now its on a Yak. Ran great on the CAP never had a problem, but as soon as it was put on the Yak, the problems started. Deadsticked several times, but that has stopped lately till, the ignition shorted in a blender (still drawing blanks on that one).
Old 07-30-2009, 11:25 PM
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Default RE: DL 50 low compressions, low power, bad idle

OMG, i put the engine back together to see how it feels and the stupid spark plug threads stripped. I didn't over tighten them, i was turning and it just never got tight. []. This just plane sucks.

Jody, what would the price be of a new cylinder and piston

Cameron

Old 07-30-2009, 11:37 PM
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Default RE: DL 50 low compressions, low power, bad idle

Cambo, do you have set of feeler gauges?

msuviper68, my apologies, I did not intend to offend you nor did I infer that I thought you were unintelligent in any way. My point is that I've seen many people with engines that have some sort of problem that they can't figure out but while trying to do so they discover that if they adjust the needles this way or that, or move the timing one direction or something else that all of a sudden the engine becomes "usable" and they just go with it. It's not that anyone is a dumb*****, just that not everyone has the product knowledge and experience to efficiently troubleshoot a problem and if I had a dime for every "experts" engine I fixed when they could not, I'd ........well I'd still be doing this because I like it.

I guarantee you, inside of an hour, I could have your engine running just like the one one my Yak, and believe me, it's perfect.


Old 07-30-2009, 11:40 PM
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Default RE: DL 50 low compressions, low power, bad idle

Send me your jug, I'll heli-coil it and return it to you no charge. If you want a piston, EERRRRRRR! Stop, The mods are going to spank me again if I finish helping you in public, gotta go PM.
Old 07-30-2009, 11:40 PM
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Default RE: DL 50 low compressions, low power, bad idle

Ya, i do have some feeler gauges


On a side note, i am also considering selling what is left of the engine and buying a DLE55
Old 07-30-2009, 11:44 PM
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Default RE: DL 50 low compressions, low power, bad idle

I will pm Jody instead
Old 07-30-2009, 11:45 PM
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Default RE: DL 50 low compressions, low power, bad idle

jedijody,

you didn't offend me in any way. I completely understood what you were talking about. thinking back, it did sound like i was offended. My apologies in return. It has anyone that I know of confused. Ive taken it home and let all the gasser guys look at it, they all just tell me to set the idle screw, or change the servo travel adjustments. But that doesn't do it. Believe me, if I could get to you so you can look at it, I would, but Washington is a bit far from Starkville, MS. haha

P.S. sorry for the horrible grammar and punctuation. I'm at MSU for aero. eng. not english
Old 07-31-2009, 12:38 AM
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Default RE: DL 50 low compressions, low power, bad idle


ORIGINAL: msuviper68

jedijody,

you didn't offend me in any way. I completely understood what you were talking about. thinking back, it did sound like i was offended. My apologies in return. It has anyone that I know of confused. Ive taken it home and let all the gasser guys look at it, they all just tell me to set the idle screw, or change the servo travel adjustments. But that doesn't do it. Believe me, if I could get to you so you can look at it, I would, but Washington is a bit far from Starkville, MS. haha

P.S. sorry for the horrible grammar and punctuation. I'm at MSU for aero. eng. not english
Well, Imainly just wanted you to knowyou don't need to put up with that and there was help for you if you wanted it, people send me engines from a lot farther away than Starkville, MS almost everyday.
Old 07-31-2009, 12:54 AM
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Default RE: DL 50 low compressions, low power, bad idle

Cambo,

It looks to me like your engine has never been fully run in. Talk to Jody about the head and put it all back together. Check the ring end gap in a couple of places and if it's less than .006" your good to go. I'll let you and Jody get together about how to index the ring for the gap checks. If you're not comfortable with using the old stuff a new and complete top end is not very expensive. If it was mine I would keep it.
Old 07-31-2009, 08:21 AM
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Default RE: DL 50 low compressions, low power, bad idle

WHICH WAY IS THE ARROW POINTING ON THE PISTON?
Old 07-31-2009, 09:04 AM
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Default RE: DL 50 low compressions, low power, bad idle

TOM, i am sending Jody the piston and ring with the head so hopefully he will have the tools to check the parts since i don't

Will keep everyone updated.

Also, how could the engine not break in, even after 20 gallons run through it?

Cameron

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