DLE-20cc Unreliable
 

All help will be appreciated. This motor starts and runs great on the bench. Just will not keep running in the air. For example: Adjusted the low and high needles so it transitions well. Runs good at high speed and idles fairly well - seems to like idling - maybe 1800 rpm, but at idle slowly slows down until it settles at maybe 500 rpm slower. Crank it up and life is good. Taxi out to the runway, makes sure it's warm, run it up a few times - all is good. Take off, fly around - do a couple of rolls, loops etc - going well for 4 - 5 minutes, throttle back to a high idle, set up for landing and it quits. - Dead stick landing. 3 times in a row.
Then did similar thing, tried to fly around on edge for a half turn, leveled it out - and it quit.
So far have replaced the fuel - always using e-free fuel with red-line 2-cycle oil, new fuel tank, carb a while ago, 15 x 8 prop, fiddled and diddled with the low and high needles - seems like always the same result. Next, I'll replace the ignition and see if something funky going on there. Otherwise, I'll replace the carb again.
Anyone hove a suffered through a similar situation? Suggest a solution? PETE

Other than the 15-8 prop being on the small side for the 20, I don't have any earthshaking suggestions. I'd recommend something like a 17-6 (preferred for most applications) or a 16-8 if you want a bit more speed. The 20 can be a bit finicky to get set right but is a great little engine otherwise. They like to be a bit rich on the low end for reliable transition to full throttle. I own two of them and enjoy them quite a bit.

I would start by going a tiny bit richer on the low end. It's hard to make a gas engine quit from being rich. Would probably change the plug next. Finally the ignition box.

david

The combination of a marginally small prop, and the fact that the engine is tuned on the ground makes me believe it is lean on both needles, not only the LS.

That engine will spin probably a bit high allready with the small-ish prop, and rev up in the air quite a bit, causing it to go lean and get hot. Hot engines do not like to throttle down.

Golden rule for gassers is to tune for flight, not for bench throttle response. Especially not if the engine is fitted under a cowling, but you don't state that, so can't tell for sure.

Ethanol free does not make a difference, it is a slightly different fuel requiring slightly differing needle settings, but with the needles set for a given fuel there should be no difference between how the engine behaves on E10 and how it behaves on Ethanol-free. I mean, the stalling when throttling back to idle for approach is not caused by the fuel, but by the for that fuel improper needle settings. I do not think E-free fuel brings any advantages, given that E10 is China's standard fuel and the engines are more than likely to be designed for it and tested on it at the factory. E-10 will require the needles to be a touch further open compared to E-free, but that is barely significant.

I had to replace my ignition box first and then I thought I had a carb issue so replaced it. Also, make sure to run a cm 6 plug at about .022 to .024 gap. My latest issue with running inconsistently was the connection from the pickup magnetic plug and the ignition box was getting sloppy. Pull it apart and back together a couple of times and see if that helps. If that helps, and then starts up again down the road the magnetic pickup may need to be replaced that will give you a new wire lead and plug. Or you can replace the plug yourself.

This has been my experience with the DLE 20 Once I figured it out it runs great with a 17 X 6 laminated wood prop. Flies my 10lb plane vertical with no issues.

Make sure not to run the HS to lean as you back off the throttle it provides a little extra fuel so the low end can catch up.

Hope you got it figured out....