My small problem didn't stop me from buying the second one.

I did'nt have the problem the first gallon. After I mounted it in a second airplane is when mine started to act up. Again, I leaned the low end and it does'nt do it anymore.

Deputydog, I think a lot of this problem may be a a combination of the rich settings in the carb for initial breakin combined with the need of all the parts to properly seat. I too noticed that once I started leaning out the bottom end and the motor began to seat everything in the problem went away. Maybe, the high idle setting is compensating for the overly rich initial needle settings. Who knows, but it worked.

Dick,
I'm right there with you on this one. Nothing beats an ear, especially after 17 years of playing music professionally. Heat gauges...what a racket. Tachs, well, RPMs are nice to know and really help identify problems as they arise. For tuning, nothing beats the Mark II eardrum. If it sound like crap, it is probably running like crap.

The engineers say that if you can't measure something, then you don't really know anything about it.

Me and a flying buddy both bought DA-50s for our Wild Hare Edges, I'm waiting for my batteries to show up in the next day or two and havent ran mine yet but we maidened his today and it too has this problem. I thought I just set the idle too low for the first flight and it quit when I touched down, thought maybe with the loss of windmilling and slowing down fast combined with a low idle did it. But, the next landing was as greasy as they come and not a burp, then I held a landing or two out till full elevator was reached, touching tail first then dropping the mains down about 6 inches or so and it shut off dead so it's definately shock related. We're both glad we found this thread and hope it stays constructive until a solution is found that works for everybody... even if it ends up being it simply needs to be run more. I'll keep any discoveries posted in our problems, good luck and keep the good info coming.

Brian

This is quite the disturbing thread for me to read since I have two DA50's I'm installing in a twin (Don Smith BF110)....... So what you guys are telling me is that I have to run about 4 gallons through these engines before I can expect a reliable idle ?

Hmmmm

Isn't that nice..... I just bought one before Easter myself. I might have bought the ZDZ 50NG has I known.

I guess I better start building that big test stand so I can get some time (4 gallons worth or so) in on the motor.

Wiz

All DA50s dont exhibit this failure, so you wont know untill you run it. But if you get one of these engines that stops running when "shocked" no amount of tweaking the needles will fix it. I believe that the people here that say that we are novices and they could make the engine reliable with needle adjustments have not seen a failing engine.

Yes, you can run the idle a liitle higher to keep it running, in fact that is how we discovered that it was a "shock" that caused it to stop running. After the engine repeatedly stopped on landings we kept clicking the idle up. Then we found ourselfs chasing the plane during taxi to stop it, thats when we discovered that abruptly stopping the plane or lifting the tail also caused the engine to stop.

So you can leave your idle high but the plane will always roll away and you will have to keep hold of it when taxiing. And when landing with a high idle the plane floats. Yes you can have different idles setup for flying, landing, and taxiing, but you really shoudnt have to.

I didnt have to do that for either of my BME50s or my 3W60 or my ZDZ80. My next engine is going to be a ZDZ50NG and I bet I dont have to have 2 different idle settings for that either.

Joe

True, if you read my previous post, I feel I have this engine without the problem. All I did was to lean the low end (a little) and run just a bit of a higher idle. Nothing special here. I could not duplicate the failure condition as explained here.

I think I may be just lucky.

And I'll bet my DA50 will fly rings around your ZDZ50, Joe. [>:] Just kidding of course. But I still think this thread has gotten a little out of control. I have had the problem. I also have never had the engine quit in flight except once in about 20 flights, and that was my fault. If I had it to do over again I would not get another engine and I would not feel it necessary to run the engine on a test stand for an extended period of time. It appears there may be different levels to this problem and some have been luckier than others. How much of this problem is the engine and how much is the mechanic, is hard to say. Yes, it is a little frustrating to have to hold your plane to keep it from rolling. I never had a problem landing it at the higher idle (it doesn't have to be that high). If you don't want to play with idle-down, just run the idle down 3 or 4 clicks on final.

I don't know what the problem is. I do know DA is a great company that has been super to me. I know the DA50 is a beautiful piece of work. One of, if not the, lightest and most powerful engines in it's class. I'm sure DA is working on the problem. These kind of things are extremely hard to diagnose and correct.

If it is a flaw in the Walbro carb, then the engine breaking in should have nothing to do with it. I have no idea if some kind of internal part of the carb that affects fuel flow needs to seat properly over time.

If it is some sort of problem related to engine parts fit someplace in the power chain or fuel delivery system, it's going to be hard to find.

But this is not a problem that would stop me from buying the engine if I had it to do over again. My engine has maybe, 4 gallons through it, and is purring like a kitten.

The problem, if you have it, is manageable. and PS: the one dead stick I had was on the second flight [:-]. Scared the heck out of me until I realized the that darn WH Edge practically flies like a trainer. It has a great glide ration. My engine quit about 75 feet up. I made a 270 degree turn and lined up and landed on the runway like nothing was wrong.

I E-Mailed DA ... ( They responded VERY quickly ) ... and I believe they are concerned about their customers and reputation.

They have had it happen to them ... they seem to be aware !

Suggested to lean out the low end as much as possible ... run more fuel through it for breakin ... then switch to Synth. at 100:1.

If that doesn't do it ... they want me to return the engine for inspection.

By the way ... I sent the engine to them over the winter ... they ran it and set the needles for me ... said I had the needles "way out" ...the problem was worse last weekend, than with the setting I had made.

I have some ideas that I will try when the weather breaks ... hope they work.

For the non-bleavers or those that respond that have never had their hands on one ... I have the E-Mails !
As JBrannon has stated ... the problem is real ... those without the problem are fortunate ... and it is not helping us just posting you don't have the problem and give some quick easy answer. I have had the exact same experience as JB .

Good luck to all !

Having to run several gallons through a gas engine before it runs reliably is rediculous. There is something wrong. Its not just the needles.

well, I don't want to start another DA 50 thread, so I post my question in this one:

The other day I nosed the Christen Eagle with the DA 50 over and broke (well just nicked the tips but it's a gonner anyway) my beautiful Mejzlik Prop[&o]. Yesterday while changing the prop (this time to a wooden one [:@]) I noticed that there was some play when holding the spinner. First I thought the engine or spinner became loose, but after inspecting both none of them caused the movement. Once the prop was removed I grabbed the shaft and noticed that there is quite some play in it which makes like a metal to metal noise. Anybody have any idea what is going on here ? Could there something be loose inside the motor ? I really didn't hit the nose that hard but I don't think it's normal either, so something must be wrong. Just wanted to ask here before sending the engine in for repair or call DA. Any suggestions ? Thanks

When I sent my engine in over the winter ... they said they changed the bearings and I believe the crankshaft because they were experiencing play in the crank.

E-Mail them with your problem and ask for advice.

I don't believe it was the nose-over. I had more severe incidents when my engine quit while flying !

I'm wondering, with all the fiddling with the carb that everyone's doing, if anyone's tried a different approach, perhaps ignition setup?

When you lift the tail of the airplane, stop the airplane abruptly, or simply close down the throttle too fast, depending on the mass of the prop, you're going to load the engine up (braking), perhaps momentarily just enough to make it quit.

I'm sure that everone's that's observed gas engines for some time have noticed that the inertia of the prop braking sometimes overshoots the low idle rpm if you rapidly shut the throttle down, then qickly regains some rpm to settle out at the final idle speed.

I'm just thinking aloud here, putting forth some ideas that perhaps were'nt considered before. It's possible it's not a fuel problem, carb problem, or mechanical problem at all??

If I experience this problem with the DA's that I have I'm going to try and advance/retard the timing a bit and see if it improves this anomaly. I might even try a different ignition.

Ignition timing follows the crank speed...Timing at 1600 rpm will be the same every time the crank is turning 1600...The engine is not shutting off because of timing....A piston port engine won't shut off no matter what the rest of the airplane does..Dave thinks excess fuel is pooling at the bottom of the reed cage and being dislodged when the attitude of the plane changes...Seems like a low needle setting just on the verge of being too lean would help...Can't say for sure, don't have a DA50.....One of my friends just got one, maybe we can experiment on his when he gets it in a plane....
Now if DA wants to donate one for testing, I have a Super Hots formerly powerd by a G62 that would be just right

RCIGN, ignition timing follows crank speed in theory....As you know, the timing on our engines are advanced and retarded by electrical means these days, and not mechanically as in years past. It's possible that the ignition isn't responding to transient changes in prop load/rpm changes at low rpm, or when a transient load is applied to the prop, such as a rapid stop of the aircraft, or shutting down the throttle. Perhaps the response of the ignition is dampened too much, and won't adjust to rapid RPM changes at low speed???

I'm just speculating here, as I can see that everyone seems to have exausted the fuel possibilities. Never hurts to try something different, regardless of how remote the possibility might be given that everyone seems stymied by this problem.

Was thinking the same thing Dave said, when the engine is inverted the reed is at the bottom of the carb. Always thought that this might be the the problem.

I will give this another try, we have adjusted the needles to this point but because we thought it might be too lean to fly we did not try to get the engine to quit.

Joe

Timing advance follows crank rpm IN PRACTICE, but so fast it seems to be advancing faster...The only timing that would stop an engine would be if it retards to AFTER top dead center..
Electronic ignition is set to advance to 28 BTDC and retard to about 4 BTDC, neither would cause the engine to stop...It can't possibly retard past the 4 or so degrees where it idles......An engine will run forever at 4 BTDC, just won't have any power......Normal timing reaches full advance at about 4000 rpm, and never goes beyond 28 no matter what rpm the engine turns...
TKG is lurking here somewhere, I'm sure he has some opinions...

Yep, I agree RCIGN. That's the way it should work, however the timing is artificially (not mechanically but electronically) retarded by the Ignition electronics.

Again, I'm just speculating here, but what if the timing, or the transient response at the low end isn't up to par?

I'm just postulating (I like that woyd) here, for even though I own two of these engines, which BTW, you machined two very beautiful prop extensions, I've yet to experience these problems, and since they're going into a twin, I pray I don't!

Some of us who don't have the problem are not trying to give you a quick and easy answer. I am just as concerned about this as you are.

JBrannon

Seems like we have had about the same experiences. I'm glad this forum started, I thought it was just me.
Some very experienced members at my club (200 + strong) tried to help with no avail.
I'm not sure ignition timing is the problem ... some 2-cycle enging dont have timing advance features, plus, after sending my engine back to DA, if it was off, I think they would have made adjustments.

Last year in an attempt to get some flying in ... I did lean the engine out until it would "just" quit when the throttle was advanced rapidly ... But it would idle OK.
Then I used throttle delay to keep it from quitting.
I then had to richen the high speed needle a bit.
It did not quit in the air at all .... only on the last flight ... turned out to be another ignition module.

I think this is why DA told me my needles were "way out" when I sent it back.
But their settings didn't work when I tried it for the first time last week. It was worse than any settings we tried.

I will go back to my previous plan.

MustangFan,

DA has provided a second ignition module and carburator, niether has changed the symtom. DA does have good support and is willing to provide evrything they can to help resolve the problem.

They DO have an engine that fails mounted on a plane at DA and thier engine fails the same way ours does. They cannot not get that engine to run reliably either. So if the Pros at DA cant resolve it on the engine they have, I dont see how we can fix just by adjusting the needles. However I have spent many hours trying and will continue to do so.

Joe