stevegauth30

My DLE 20 (second season) is idling strange. It's picking up RPM's on it's own. Sometimes it won't idle down, and stay at around 4000, and sometimes at low idle, it will start to pick up RPM's up as hige as 5000. That rpm on this plane will take off. I can't fly this way. Here's the setup;
great planes super skybolt 60
17x4W prop
stock ignition
CM6 plug
LIFE 6.6 2100
Techaero ultra IBEC
Inverted wrap around pitts.

it ran great at the end of last year, but at the first start up this season, it wasn't running well so I pulled the screen and it had all kinds of junk in there. I also run a three filter setup. Fuel can, tank, and in-line. It runs great now, aside from this. Can it be debris still? Timing? I can't seem to figure it out. I installed all new lines too.

ahicks

My Feedback: (2)

You didn't mention if you had tried adjusting the carb?

Have you tried running it without the cowl so you can see what your servo is doing when the rpm's start climbing?

All Day Dan

My Feedback: (5)

I have had the throttle plate come loose. It gave me the same symptoms. When all else fails, remove the carburetor and check it out. Dan.

stevegauth30

Yes, a, I did adjust the needles. They were way off. Like I said, it runs great now. It wouldn't idle before and was too rich on top. I feel like the needles are set good . The cowl is off and I wasn't seeing the throttle moving when it would happen. I'll check it again just to be sure once the neighborhood wakes up. Too early yet. Thanks.

stevegauth30

Ill also look into that too Dan, thanks a lot.

stevegauth30

Can having too small of a prop cause anything like that? No clue why, the wrong prop was on it. I usually run a 17*4W prop but I was just looking at it and there was a 15*6 on there. I'm lucky I didn't over rev it. Glad I noticed it. I also just checked all screws for tightness. They all seemed ok.

stevegauth30

Well, putting the correct prop on sure made it run even better. Lower idle and more realistic RPM's. It idles around 1850 and tops out around 9200. But the problem still persists. I did check all the screws on the carb for tightness. I'm a little stumped right now.

stevegauth30

Oh and by the way, when it does it, the servo does NOT appear to move. If it does, it's so slight that I can't see it, and wouldn't be no where near enough to hit 5000 Rpm.

Truckracer

My Feedback: (19)

5000 RPM means the engine is getting quite a bit of fuel and air from some sounce. If nothing is moving, sounds like Dan's solution might be well worth looking into. That air and fuel is coming from somewhere!

Now if its just picking up 500 or so RPM, which could be 1000 or more with a prop that is too small, check out the DLE 20 carb replacement thread for possible solutions.

stevegauth30

Just curious, but wouldn't it be like that all the time? It will idle great, then you advance the throttle a tiny bit, and it will just keep going. Then I'll blip the throttle a bunch of times and it will finally drop back to idle. Some times I'll only have to blip it a few times, and sometimes like 15 or 20 times. I'm thinking your right though, it's gotta be leaking air somewhere.just don't know how to find out where.

stevegauth30

Will it help if I post a video?

Truckracer

My Feedback: (19)

Did you inspect the throttle plate to be sure the retaining screw is tight? If that screw comes out your engine is toast!

ahicks

My Feedback: (2)

I'm like All Day Dan's idea more and more. You've checked the screw that holds the throttle plate in place - inside the throttle barrel? Doesn't happen often, but they will come loose on occasion, allowing that throttle plate to bind and not allow it to close completely.

To allow rpm's to build to 5k, it almost has to be something that will allow an increase in air AND fuel? To do that and come down after blipping the throttle a few times, sounds like the throttle plate trying to recenter itself....

stevegauth30

No. I'm gonna pull the engine off so I can go over it right. I'll let you know if I find anything. Am I correct in saying a walbro k10 kit will work to rebuild? Exactly what carb is on there? Anyone know?

stevegauth30

I'm still a newbie with gasses so I'm trying to figure out exactly what you guys are even talking about. That's why I ask about the carb so I can do some research on it.

Truckracer

My Feedback: (19)

The 20 comes with a Walbro clone and the K10-WAT kit should work just fine. You could also use the D10 kit and it is a bit cheaper but includes fewer replacement parts. For comparison, a very similar WT962 Walbro carb is used on the Valley View 20. Its good to keep a kit on hand but you may not need a rebuild if your rubber parts are still soft and pliable.

stevegauth30

Ok, thanks truck racer.im looking at the throttle and doesn't look right to me. The idle screw isn't even close to the disc when closed. Is this right?

Truckracer

My Feedback: (19)

You're right, that looks like the throttle is half open. Remove that carb and check the throttle plate retaining screw.

By the way, most people remove those idle stop screws and just let the throttle servo set the idle speed.

By the way, why are we discussing this on a nice day when we could be flying? For me ... the sun is out but the wind is blowing like a hurricane.

stevegauth30

Yep. Same here. This morn was perfect, but I was out giving estimates. I get home, and wind. Typical.whats weird though is it was idling at 1800 or less just this morning. Why would it look half open and idle great? Odd. So pull the carb right off? That's where the throttle plate retaining screw is?sorry for all the questions. And thanks.

stevegauth30

Your right. That screw was about to fall completely out. But now it's binding up at that point in the pic.

Truckracer

My Feedback: (19)

You'll have to carefully center the throttle plate and shaft in the bore before you retighten the screw. Adjust so it doesn't bind in any way. Be sure to use a bit of red Loctite on the screw threads. If you have some, a tiny bit of penetrating green Loctite works great applied to the threads after the screw is in place. Use rather than the red. Examine the shaft closely as they have been known to break at the screw hole.

A removed or disconnected throttle return spring can also cause binding in some cases. Best to just leave it in place as it comes from the mfgr.

stevegauth30

I was just about to ask about the loc tite. I think she'll run good again now. Thanks guys. I'll get it fired back up and let you guys know.

a70eliminator

Just to clarify something here, are you saying you locktited the idle stop screw seen in the picture? Because the throttle plate screw they were talking about you can't see in that pic, hopefully it was the throttle butterfly screw that was loose and your now fixed!

"That screw was about to fall completely out. But now it's binding up at that point in the pic".
This statement is what confused me.

All Day Dan

My Feedback: (5)

Steve, is that screw flattened out or straight? Is there any locking device on it? Dan.

stevegauth30

It was the butterfly screw that was loose and now loc tited. It solved the problem. Now needs to be re tuned though. I'm not yet too good at finding the sweet spot. Took me a while the first time but I had it to where it would idle in definately. I think I'm getting close. Dan, I don't understand what you mean. It's just a Phillips head machine screw. There may have been a split washer if that's what you mean by locking device. I did get it centered and closing completely without binding. I remover the idle stop screw like you said.