stevegauth30

Hi, it's me again, Steve, the first time gasser. I have a DLE 20 on a super decathlon 120. I have only run a bit over a half of a gal through it, so I know it's still breaking in. I finally changed the stock plug to the NGK after a couple of flights, and it did start better, but still isn't running smooth. A guy on here who seems to be a smart guy with a lot of gas under his belt told me to richer the HS needle an 1/8 from factory settings and take off and with a constant throttle setting, do a big gentle loop. If it four cycles at the bottom of the loop to richer the HS an 1/8. Repeat till it doesn't four cycle at the bottom. So I've done this before every flight, but it's still not smooth. It sounds like it skips at high throttle and kind of sounds like its four cycling at lower settings. Another thing is that I have no mid range. It's like all or nothing. By the time the stick is at maybe 3/8, it's screaming. Is this my linkage or radio setup, or does it sound like out of adjustment?i did lean the LS needle about an 1/8 and it seemed to get a little better. I just don't want to lean it too much and heat it up.it also wants to die after a minutes at 1900 to 2000. Rich? I'm trying to get it to idle around 1800 to 1900. Any thoughts? Thank you as always, steve

pe reivers

This "guru" gave you wrong advice.
First tune the idle setting, leaning the LS needle, until the engine hesitates to accept throttle when cold. <font size="4">( when cold)</font>, that will be the idle limit.
Then, if at the bottom of the loop the engine sputters, <font size="4">lean </font>the HS needle until it stops doing that. That should get you close enough to begin with.

PS
This assumes that you have your HS needle rich to begin with.

skillet92

Gas throttles are not linear like glow. You will need to set up a mechanical offset like a long arm on the carb and a a shorter arm on the servo to get a more smooth transition or if you have a throttle curve on your radio use it. It will limit the travel for the first part of the stick. Really once that butterfly is a little over halfway the engines changes very little

w8ye

My Feedback: (16)

Glow throttles are not any more linear than gas throttles

stevegauth30

That's actually how it is. I put the arm extension on that came with it, and it's on the closest hole on the servo. Hmm, I'll try some different things.

ahicks

My Feedback: (2)

I don't think it's as much about different length arms as it is about their relationship with each other? This is a link to the sticky at the top of the gas section. In post #22, down near the bottom, you'll see a diagram that might give you some ideas regarding the extreme differential required to get this right? The servo arm ends up pointing nearly straight at the throttle arm whith the trans. stick down and throttle arm closed -

http://www.rcuniverse.com/forum/m_8673009/tm.htm

I'm struggling with the logic behing the loop thing - but I've never tried it.

microdon2

My Feedback: (47)

DLE 20 running question - the engine seems to start and run fine, but I can't bring the idle down low or kill the engine with the throttle. This just started happening - was running fine till a few weeks ago. I took the carb off over the weekend thinking the cause was a loose throttle plate, but it looked fine - seemed to be centered and closing fully. The screw was slightly loose and I tightened it. Now the engine idle is not coming down - even when I close the throttle completely - and increase my throttle end point. I checked the linkages and they look fine. It's behaving as if the throttle plate is off-center. Could that be it, even though it looked fine?

Could there be another air leak somewhere? Any other ideas?

Indiomike

My Feedback: (5)

microdon

Take a look at the throttle plate. It has an indentation on it (almost looks like a half moon). Open the throttle by hand so you can see the inside of the throttle plate. Carb will have to be removed from the engine to do this. That indentation should bump up against the throttle shaft for it to be in correct orientation.

This may or may not be your trouble but I think it's worth looking at. When the throttle plate closes completely with the throttle spring hooked up it should kill the engine. I assume you have removed the idle adjustment screw so that spring tension will completely close the throttle.

You can see how the indentation works by looking at the choke plate. It has two indentations. Put choke in open position and look on the side opposite the screw head. See how they butt up against the choke shaft.

Oh, don't forget the loc-tite on the plate screw.

Mike

ahicks

My Feedback: (2)

To do what you're describing, it has to be getting air from somewhere, right?

If the engine/plane is together, using "easiest stuff first" logic, you might want to fire it up and spray some ether or something at the front bearing area, cylinder to crankcase area and carb base - to see if you might be sucking air in one of those areas?

Once apart, the easiest place to check is the carb plate. You might want to have another look at that while holding the carb bore up to a light so you can spot any misalignment more easily? ANY light, other from the notch in the plate, has to be dealt with.

There's also a chance air is being sucked in around the throttle shaft too. Most easily found by checking for a lot of slop between the shaft and carb body.

Good luck!

microdon2

My Feedback: (47)

Indiomike \ Ahicks -

Thanks for the suggestions. Will look at this again tonight.

Mike

microdon2

My Feedback: (47)

Since I've been using Synthetic oil I'm thinking of moving from 32-1 to 40-1, for better engine running and performance. I know the DLE's are recommended for 32-1, but I'm thinking that's more for natural oil \ break-in. Any comments? I'm also switching from Echo to Redline.

Thanks.

ahicks

My Feedback: (2)

I might consider the 40:1 move on the 30, but the 20, my feelings are that might not be a good plan.

First, there is no performance to be gained by the move.

Second, maybe not as much an issue anymore, but the 20's were taking out their bottom ends pretty regularly when they first came out. With the first reason in mind, and the potential for that bottom end letting go, my engines will stay on 32:1, dino or synthetic.

kmeyers

+1 ahicks
What do you think you will gain at 40:1?
Been running 32:1 for years with no issues.