Originally Posted by tailskid2

Have a friend with a new DLE 20 V2 and the idle problem seems to be history! Right out of the box it ran great and the transisition from full throttle to idle is spot on

Good to know!!

The frustrating thing about my limited experience with these smaller displacement DLE's is that no two are the same it seems. There are three 20's at our club and four or five 30's. No two take the same technique to cold start or hot start. Some will hand prop, some refuse to fire or even prime without putting a starter to it. Some will idle while some are lousy, some can fly all attitudes without a *miss*, some *miss* at one particular throttle setting and some are horrible all through out the curve. I think it all boils down to poor Quality Control. Especially of the reed/fuel metering system. It's hit or *miss* there. I will say tho' and it's easy to tell; if your engine runs well on the stand and has a miss or burble in flight then it has to be poor/errant cowl flow. As re-plumbing the diaphragm pressure vent will cure the 'in flight *miss* anomaly' 98% of the time, perhaps the manufacturers should visit FG and get on board with a factory mod to design? Hmmmmmm...............

Having said all that, no one at our club complains about the larger, 60cc and larger DLE's. Those are the guys who really promote DLE earnestly and what steered me to the 20 in the first place.........................

Well. Darn.

Thought the reed block mod cured my engine 'loping' or hunting at idle, but no.

Here's a video of the engine idling. It's done this since day one. So far I've re-plumbed the diaphragm pressure vent to the fuselage (pill bottle) to cure an in flight *miss*. That worked wonderfully. Then I did the reed block lapping mod, that went well but the engine wasn't any better for it. It always hand propped well. As it was idling a few 'experts' at the field had a go tuning the needles every which way to no avail. A few thought the low mixture was off or the throttle servo was wandering or I had a loose throttle linkage but no. Then today I swapped out the stock ignition module for an RCEXCEL unit and the engine still loped @ idle.

Thoughts of where to turn next? I've had the carb pretty much torn down doing the reed mod, took the needles out and blew air here and there, the screen is clear and the butterflies tight.

I suppose in the end game this was a warranty issue from the start, but considering all the tearing down and modding I have done thus far I'm sure DLE would not honor the warranty. And I certainly wouldn't blame them.

Some say to just fly the plane and 'break-in' more. The surging tho' can bring the rpm up quite a bit more than what is seen in the video. I can't get the plane to slow enough for a controlled landing run out unless I kill the ignition on short final = no option for go-around. Not really an option for me.

Is there a Walbro application someone might recommend? I'm tempted to just order a whole replacement carb from DLE but that seems running circles. Thanks in advance;


Doug

Motor Vid (0 min 39 sec)

Is that the lowest she will idle?

Yup.

Not sure of the rpm there, but if the idle would stabilize there, at the bottom of the lope (sometimes it does, like right after start-up, it seems that it lopes after it gets warm) it won't creep on the hard surface runway. If I try to get the idle lower (so I can slow it down on approach) it will cut out on the bottom of the lope.

Thanks for reading..................

An engine surging like that is often lean. Take that with the fact it's sometimes dieing, and I'll bet it is lean. Try about 1/8 turn richer on the LS, then reset your idle. Do not pay attention to how smooth it's running or what it sounds like. Pay attention only to the way it runs. See where that leaves you.

The tendency is to try and get them purring like a V8 on idle. Bad plan..... it'll leave you lean every time.

Thanks 'AHicks'! I'll do just that.............should I reset the top end with every 1/8th turn on the bottom?

I'll approach it with an objective mind and do as you suggest but there were a few hands into it this afternoon and the bottom end needle was turned in both directions. The idle speed did pick up and/or drop with every turn in each direction and I reset the idle accordingly but once I got a reasonable idle speed...............it started surging...............play with it some more.............thanks so much for the suggestion!

Not knowing any more than I do about what you've done, I'd say yes. Go ahead and check the high speed setting while you're at it? Going richer on your low speed will drop your idle speed for sure. You'll need to bring that back up.

Keep in mind these ground adjustments are going to be close when you get it air born, but once in the air there's a very good chance you'll want to adjust both the high speed and the low speed further - to address problems only seen once in the air?

That's why you're seeing guys tell you to fly it and get more time on it. Getting it running real nice on the ground is a waste of time? Your real objective is to get it running right in the air?

Thanks again.............ironically, the engine is pure joy in the air, just couldn't or wouldn't want for anything more. Super smooth and as it's in a .60 size plane, buckets of power. Unfortunately when I try to land the surging makes for a nightmare approach. As it surges it carries way too much speed and you just can't stabilize the approach. I try to drop the throttle trim to get it to calm the heck down but then it dies and I land long.

It's like when we were all beginning and the seasoned pro's would insist; "Lay off the throttle on final. You'll never get a stabilized glide path adding and pulling off power!" Yup, flying this motor in it's current state is bringing back memories. Of sucky landings!!

When right they're a sweet heart. Figuring out how to get them right a PIA for a lot of guys...

Asking for/getting just a few rpm's to help flare is easily done when it's right. Hang in there. You'll get it!

Thanks pal. Appreciate the encouragement.

Just a little frustrated at this point as my intro to gassers was a Mintor 33 that was a real horror show;

Hey Doug, I wanted to get back with you on the Mintor 33. Mintor told me that nothing has been redesigned on any of their engines. The problem with the engine was the companies sudden growth due to sales in the US, so they outsourced pistons, rings and sleeves. They were also producing in their own factory. What happened with the parts was that both, the in house and the out sourced parts were used in production. This is the reason you cannot track faulty engine with serial numbers. They just don't know which engines are bad until the modeler using them. Early on we were repairing all the engines but some of the parts we had were from the out sourced supplier and the tolerances were off. So we ended up sending out bad engines. Now we are just replacing engines with the latest that Mintor has sent us. From what Mintor is telling us under the new ownership, that they have destroyed the defective parts and are starting from scratch with all parts for engines.

That acknowledgement was after three blow ups and three returns for service.

And now this with the 20 after hour after hour tinkering with something 'new' out of the box and still problems.

lol, it's just typical of me tho'. I'm the guy who pulls a two slice toaster of fifty in a row off the shelf at Wal-Mart and when I get it home it only toasts three sides. I'm on a first name basis with the gal at the return counter at Lowes too.

Thanks again for the help, yup, it'll all work out in the end. It always does!!

I hope this all works out for you. I too have been looking at a 20cc engine. I'm saving all my pennies.

For a scale plane the Zenoah G20 is a good entry level engine. I have one in box going into a Hangar 9 Hellcat. There are quite a few at our field. Reliable, easy to tune and start and more often than not you hear; "The needles are still at the factory setting, I never touched them. The engine runs like a top". Which is encouraging. The downside to the Zenoah's is that they are a bit on the heavy side ergo good for scale and basic aerobatics but probably not for 3D, but having said that there are a few die hard Zenoah guys flying 3D with them.

I'm new to gassers so I decided to try an 'across the board' trial with a few popular makes to see which suits me best. So far I own(ed) a Mintor, EME, DLE, DA and an OS.

The DA's reputation is well earned and speaks for itself. A wonderful engine. As above; the Mintor was a big let down and the DLE isn't getting high marks in my book. These reports are all very subjective tho'. It's like the great Ford/Chevrolet debate. Just gotta go with what works for you. It's an uphill climb~!

Motor Vid (0 min 39 sec)

Well, still hunting for a solution for my surging idle. I had another lead from a discussion regarding a DLE 30 that wouldn't settle down either and that was traced to a loose throttle butterfly. I had hopes, but no, mine was solid.

I've relegated the task from "I wanna get this engine to run well so I can enjoy my plane........" to; "I'm going to learn a lot about gassers because this engine is buggy"..............

So, just *bumping* this for my own musing and maybe garner more input.

It's definitely time to 'think outside the box'. Not sure what's wrong with the motor but 'needles/mixture settings/reed blocks/ignition and carb maintenance are not issues. That's all been addressed 4X.

One aspect I'm looking at now is that; every time I perform a possible solution and fire the motor it runs extremely well until it gets up to operating temperature. Then it starts to surge @ idle. So it occurs it's 'heat' related with regard to expanding machined joints. The surge, I suppose, is air entering the crank case and leaning the mix toward gaining rpm? A theory.

There are no fuel leaks so no obvious place to start. I have already lapped all the reed block/carburetor rear stage faces and reassembled with Permatex 'Form-A-Gasket'. Torqued down the cylinder and rear case bolts.

The next try is to make my own rear case section gasket, although there is no stock design for one and use gasket sealer there.

See what happens..............

I question the servo geometery. I find I can fine tune my idle much more with proper geometery.
Your stick to servo control horn ratio movement should not be as much on the lower position as the upper half.
A servo with good centering is a must for getting that low consistant Idle.

Originally Posted by kerwin50

I question the servo geometery. I find I can fine tune my idle much more with proper geometery.
Your stick to servo control horn ratio movement should not be as much on the lower position as the upper half.
A servo with good centering is a must for getting that low consistant Idle.

Excellent point. OK, thanks. I'm on it!

Are you suggesting a non-linear throttle curve? That could be easily addressed. The 'linkage' geometry is a straight shot: servo (EZ connector) to throttle body (nylon ball link) and there is no slop there.

<edit> I will start with a new throttle servo as well. Certainly the throttle servo was suspect and it was scrutinized for non centering/deadband errors 'visually' while the motor idled but it seemed solid. That doesn't mean, considering the idle 'lope' is only a few hundred rpm which would translate to a click or two at the most of trim, that the servo isn't holding a critical center. The servo could be hunting. That could very well be.

I had other issues (servo current feedback damage to the Rx) with another model and came across a JR notice that the JR HV821HS servo, although WIDELY used in large 3D gasser models @ the throttle position is not recommended for gasser applications due to vibration issues. I swapped that servo for a high torque high voltage Hitec application. It didn't occur to me JUST NOW that I am using that same servo in this DLE 20 application.


Thanks Kerwin...............