Can anybody tell me if the DL 50/DLE 55 runs 2 different idle points, about 200 rpm difference. If somebody isolated and fixed the problem and is willing to share the findings, I'd be very appreciative.

After staring the engine, I have to trim up to flight levels but when throttling up and then back down, it will be considerably higher making the plane roll forward, even on grass. But then, after a few seconds (10-15 seconds), the idle will go back down to very unreliable levels.

Flying my Yak with such inconsistent idle makes me very nervous. I have to trim it up several clicks for flight and bring it way down when landing.

I have experienced countless deadstick landings due to bringing the throttle trim too low but sometimes the Yak has to be brought in at very low rpm so as to not overshoot the landing, adding to my worries. Thanks.

What you running for a throttle servo?

Also may need to tweak the needles a wee bit? Either way youll be best served with a flight idle mixed to a switch to prevent flame outs...

Hey Robbin, thanks for the feedback!

I'm running a JR DS821 on throttle.
The engine runs very well in the mid range, no burping and has plenty of power as in unlimited vertical with 17 lb plane spinning a Menz 22X10.

Have you heard of the inconsistent idle of early DLE 20 engines caused by the original CDI units. I was wondering if something of the sort could be troubling my DL 50.

Originally Posted by Doublesixes

Hey Robbin, thanks for the feedback!

I'm running a JR DS821 on throttle.
The engine runs very well in the mid range, no burping and has plenty of power as in unlimited vertical with 17 lb plane spinning a Menz 22X10.

Have you heard of the inconsistent idle of early DLE 20 engines caused by the original CDI units. I was wondering if something of the sort could be troubling my DL 50.

Are we talking about a DL50 or a DLE 55 here? Completely different engines. Neither engine ever had the ignition advance problem the DLE 20 had.

You can try opening the low speed needle a little bit.

low end does sound lean

Thanks for the feedback guys. After rechecking all fuel lines, servo linkage, and a carb cleanup, will proceed to open the low needle. I know it will burp, even with a 1/16 turn but I'd rather have burping than risking another flameout.

Sure. give that a try. I think you're on the right track. I also am wondering is your pushrod a solid piece with ball links? If so it couldbe possible that your servo is not precise enough. I have been HS 5665MH servos and they are very precise and repeat any point I set for idle all day long. I always try to set my idle with a hot engine also (normal operating temp.).

I too have had my share of dead sticks!

I had an idle issue like this with my bme 58 after 20 or 30 gals of gas through it I believe it was low on compression and it had an erratic idle when hot. it would be fine on take off but landing the idle would be much higher. I sent it back thinking it was a carb issue and tom rebuilt the carb and sent it back but it still had the problem so It went back again for a full rebuild. I would check the compression on it.

Lean runs can cause low compression....and toasted rings & pistons......

Originally Posted by corey24

I had an idle issue like this with my bme 58 after 20 or 30 gals of gas through it I believe it was low on compression and it had an erratic idle when hot. it would be fine on take off but landing the idle would be much higher. I sent it back thinking it was a carb issue and tom rebuilt the carb and sent it back but it still had the problem so It went back again for a full rebuild. I would check the compression on it.

If you have one that idles faster when landing then on takeoff and then calms down after you land it's too lean on the low end. That or it's getting hot.

I'm still repairing the belly of my Yak but if I'm lucky enough, Saturday will be the day to fly her with the new low speed setting. I'll post on here my findings.

On another note, have you guys checked that new Evo 62 with EFI? Maybe that's what I needed to prevent damage to my bird due to flame outs....

I think this is the answer to your question - "I'd rather have burping than risking another flameout"

If you try to clean up that "burble" in mid range with your carb adjustments, you're very likely going to be lean, or right on the very edge of it, and flame outs will be a common occurrence.

You know about the single step ign. modules shipped with the earlier DLE20's, but that is only one of the 2 more probable problems many learned about with that engine. The other is this same exact scenario you've described above, and ANY 2 stroke is very capable of doing the same thing, for the same reason - the low speed needle (or jet) is lean, resulting in the 2 step idle, or "high idle hang".

The combustion chamber is hot after it's been run for a while, and it's not getting quite enough fuel to cool down immediately when the throttle is closed. It takes a second for that to happen. Doubt you're hurting a thing when run like that, but that hang can get frustrating (and expensive?), and it might even be a little easier to start if you richen the LS just a hair?

I've also heard of that symptom referred to as "Long idle".