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Old Jan 25, 2014, 08:52 PM
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AtomicFlyer's Avatar
United States, NM, Los Alamos
Joined Jun 2008
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Help!
DLE-30 Dies When Inverted *FIXED*

EDIT: The problem was fixed with a new carburetor. See post #80. Thanks.
============================================

Hey Guys.

My DLE-30 dies when inverted. I'm hoping someone might see something that is causing my problem.

The Facts:
-This is my first gasser. I bought the DLE-30 new a couple months ago.
-I've put about 3/4 of a gallon through the engine. I'm using Redline synthetic mixed at 32:1

The Good:
-It starts very easily and idles nicely. It has fine transition to full throttle.
-I can do loops, rolls, snap rolls and upright harriers just fine. Upright, the DLE does everything I ask it to.

The Bad:
-When I roll inverted, the engine dies. Sometimes it dies within 5 seconds. Sometimes it takes 30 seconds or more to die. Occasionally I can get more than a minute of inverted figure 8s, but it eventually dies.
-This has happened since the engine was new.
-Today I tried a bunch of different things, took off, rolled inverted, and waited. I had to do about 6 dead stick landings.

What I've tried:
-Before I started the engine the first time I did the reed block sanding modification.
-I've re-plumbed the gas tank 3 times. I'm using a 3 line tank and I'm quite confident that the Walbro felt clunk is moving freely.
-I recently did the carb equalization mod using the film canister.
-I've tried various high speed needle valve settings including running rich enough to have quite a bit of burbling at high speed upright level flight.

What has worked:
-Today, at the suggestion of one of my club-mates, I inverted the fuel tank in the plane. I actually got more than a minute of inverted fight. I pushed out of inverted in a half outside loop to upright and the engine died at the top.
-My club-mate is convinced that proves it's something in the tank, but I'm not convinced.

What I'm going to try:
-The only thing I can think to change right now is the gas tank. I bought a Fiji water bottle and I'm planning to build a tank using a PSP cap.

What I've researched:
-I've read a dozen or so posts on various forums about others that have this issue. The general consensus there seems to be to do the carb equalization mod and to richen the high speed needle valve.

I'm hoping to get this issue resolved because I like the ease, flight time, and noise of the gas engine. But I like to fly inverted for long periods so I need to resolve this or find another power plant.

Please have a look at some of my photos and let me know if you see anything wrong.

Thanks in advance,
Marc
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Last edited by AtomicFlyer; Feb 23, 2014 at 07:28 PM.
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Old Jan 25, 2014, 09:41 PM
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United States, NC, Faison
Joined Jan 2011
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I see a couple of things that I would change. Get rid of the separate filler tube and get a T fitting for the fill line. The extra filler could be keeping the clunk from moving around.

Get rid of the felt clunk, it can get clogged in the tank.

Extend the vent tube further in the tank and turn it up till it touches the top of the tank.

Lastly, install about 12 -16 inches of supply line to the carb with an inline filter. Make sure that the vent line is free and not kinked up.
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Old Jan 25, 2014, 09:41 PM
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United States, CT, South Coventry
Joined Jun 2011
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Going to follow this one closely as I'm having virtually the same issue. Several have told me low speed is too rich so as soon as time and weather permits I'm going to try the suggested tuning procedures and see what happens.
Keep us posted and I'll do the same.

Thanks
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Old Jan 25, 2014, 10:45 PM
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United States, TX, Leander
Joined Sep 2003
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Are both clunks (filtered and not) heavy enough to move around in the tank? Does it do it soon as you take off and roll inverted or does it need to run awhile before it does it. I sometimes add weights to my carb line to weigh it down to keep it in the fuel, (3/8 nuts work pretty good.

I've never had a fill line interfere with a carb line. It wouldn't hurt to check the carb screen filter (inside the carb) for filter fibers to at least eliminate that. My dle 30 never did anything like this, BUT, I did replace the carb with a real walbro carb. I could never get a reliable idle low enough to keep the plane from walking away from me. The new carb solved that.
Edwin
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Old Jan 25, 2014, 11:10 PM
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AtomicFlyer's Avatar
United States, NM, Los Alamos
Joined Jun 2008
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Quote:
Originally Posted by rjstrickjr View Post
I see a couple of things that I would change. Get rid of the separate filler tube and get a T fitting for the fill line. The extra filler could be keeping the clunk from moving around.

Get rid of the felt clunk, it can get clogged in the tank.

Extend the vent tube further in the tank and turn it up till it touches the top of the tank.

Lastly, install about 12 -16 inches of supply line to the carb with an inline filter. Make sure that the vent line is free and not kinked up.
Thanks for the tips. I have a T on order to try out the single clunk. All the guys in my club run that way.

Quote:
Originally Posted by Rich215 View Post
Going to follow this one closely as I'm having virtually the same issue. Several have told me low speed is too rich so as soon as time and weather permits I'm going to try the suggested tuning procedures and see what happens.
Keep us posted and I'll do the same.

Thanks
I've only tried adjusting the high speed needle valve. Let me know if the low needle adjustment helps.

Quote:
Originally Posted by edwin1 View Post
Are both clunks (filtered and not) heavy enough to move around in the tank? Does it do it soon as you take off and roll inverted or does it need to run awhile before it does it. I sometimes add weights to my carb line to weigh it down to keep it in the fuel, (3/8 nuts work pretty good.

I've never had a fill line interfere with a carb line. It wouldn't hurt to check the carb screen filter (inside the carb) for filter fibers to at least eliminate that. My dle 30 never did anything like this, BUT, I did replace the carb with a real walbro carb. I could never get a reliable idle low enough to keep the plane from walking away from me. The new carb solved that.
Edwin
The two clunks seemingly move around very easily. The felt clunk is quite heavy when saturated with fuel. But I will open it up to have a look.

Do you have a link to the correct Walbro replacement carb?

Thanks,
Marc
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Old Jan 26, 2014, 08:36 AM
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USA, AZ, Glendale
Joined Nov 2008
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Certainly sounds like a fuel delivery problem to me. I'd get rid of the tygon as your clunk line an use something a little less stiff. I prefer to use Hayes fuel line because it's really flexible. However, I have completely switched to Rotoflow Tanks. Inverted or knife edge your clunk is always in fuel. I also use the QuikFire fuel filter and balancer. The quick-fire is $25 shipped, but you will always have a 1/4 ounce of fuel directly at the carb. The Rotoflow and the QuikFire together are a fairly expensive change, but I've not had any fuel delivery problems since switching. Even if air enters the QuikFire from your tank, it doesn't pass through to your carb.

Not saying this is the way you should go, or this is the be all and end all, just trying to give you another option or idea.
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Old Jan 26, 2014, 08:46 AM
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I switched to a WT-742-1. Not saying thats the only carb that will work, but it works for me. It has a 12.7mm venturi.

This is a strange problem, I've not heard of a gasser that died inverted. I gotta say I like the work you did on the stopper, very thorough.
Edwin
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Old Jan 26, 2014, 09:53 AM
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United States, NM, Los Alamos
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Quote:
Originally Posted by Dooz View Post
Certainly sounds like a fuel delivery problem to me. I'd get rid of the tygon as your clunk line an use something a little less stiff. I prefer to use Hayes fuel line because it's really flexible. However, I have completely switched to Rotoflow Tanks. Inverted or knife edge your clunk is always in fuel. I also use the QuikFire fuel filter and balancer. ...
Thanks for the suggestions. I've not heard of the QuikFire. Do you have a link?

I know tygon hardens over time in gasoline. And out of the package it was pretty stiff. But my tygon got super floppy once it was in gasoline. When I take the tank out of the plane the clunk has no problem at all flopping around with gravity.

Quote:
Originally Posted by edwin1 View Post
I switched to a WT-742-1. Not saying thats the only carb that will work, but it works for me. It has a 12.7mm venturi.

This is a strange problem, I've not heard of a gasser that died inverted. I gotta say I like the work you did on the stopper, very thorough.
Edwin
Thanks for the carb number Edwin. If you google "dle30 inverted" you'll find quite a few threads on this issue. But there doesn't seem to be one fix. In my club, I tend to fly inverted a lot more than the other guys do.

Marc
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Old Jan 26, 2014, 10:19 AM
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http://www.jlproducts.net/ProductQuikFire.html

You can check out the Rotoflow tanks there too if you'd like. They are made by the same company/person. I see they've gone up a bit in price too... ack. Still, I'd say it's worth it.
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Old Jan 26, 2014, 10:29 AM
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United States, NM, Los Alamos
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Quote:
Originally Posted by Dooz View Post
http://www.jlproducts.net/ProductQuikFire.html

You can check out the Rotoflow tanks there too if you'd like. They are made by the same company/person. I see they've gone up a bit in price too... ack. Still, I'd say it's worth it.
Thanks for the link Dooz. And thanks to everyone for the suggestions. Another guy suggested getting one of the Fortitude pre-built tanks. I'm starting to accumulate a large list of things to try.

I'm going to wait to hear back from Troy-Built (where I bought the engine) to see what they say first. Then I'll start buying and replacing! :-)

Marc
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Old Jan 26, 2014, 10:54 AM
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At what throttle position is it causing problems, full, mid, low or all? How much if any mid range burble are you getting? My 30 had the same problems at anything below full throttle, a bit of tuning on the LS needle fixed mine.
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Old Jan 26, 2014, 11:02 AM
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United States, CT, South Coventry
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Quote:
Originally Posted by AtomicFlyer View Post
Thanks for the link Dooz. And thanks to everyone for the suggestions. Another guy suggested getting one of the Fortitude pre-built tanks. I'm starting to accumulate a large list of things to try.

I'm going to wait to hear back from Troy-Built (where I bought the engine) to see what they say first. Then I'll start buying and replacing! :-)

Marc
Here's a little more info on what mine does and what I've tried to do to fix it.

Mine died when rolling from inverted to upright and the nose pointed up.

I changed the stock fuel tank to the 4titude 16oz after the first time it did it.

The second time with the new tank only about 2oz of fuel had been used when the engine quit after rolling upright from inverted.

After the second time I changed the vent line around because it was quite long and there was a portion of it that would fill with fuel when inverted and settle into a low spot when rolled upright so I thought maybe the tank was having trouble venting because of that.

I haven't had an opportunity to fly it since I've made the changes in the vent line because it's too frickin' cold and windy.

I'm going to try the tuning procedure that was reccommended to me and improve the transition from low to high speed and hopefully, between that and the fuel vent line changes, it won't quit on me again.
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Old Jan 26, 2014, 11:05 AM
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Quote:
Originally Posted by whitewolf View Post
At what throttle position is it causing problems, full, mid, low or all? How much if any mid range burble are you getting? My 30 had the same problems at anything below full throttle, a bit of tuning on the LS needle fixed mine.
This an excellent point. MIne seems to have that low to mid range gurgling sound to it.
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Old Jan 26, 2014, 11:07 AM
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Quote:
Originally Posted by AtomicFlyer View Post
Thanks for the link Dooz. And thanks to everyone for the suggestions. Another guy suggested getting one of the Fortitude pre-built tanks. I'm starting to accumulate a large list of things to try.

I'm going to wait to hear back from Troy-Built (where I bought the engine) to see what they say first. Then I'll start buying and replacing! :-)

Marc
lol yep, we are all just spitballin' but that's the beauty of a forum. It will probably end up being something nobody thought of, or maybe they thought it, but chose not to contribute. Hope you get this worked out, and if you do, let us know what it was so I can add it to my knowledge bank!
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Old Jan 26, 2014, 11:09 AM
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AtomicFlyer's Avatar
United States, NM, Los Alamos
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Quote:
Originally Posted by whitewolf View Post
At what throttle position is it causing problems, full, mid, low or all? How much if any mid range burble are you getting? My 30 had the same problems at anything below full throttle, a bit of tuning on the LS needle fixed mine.
I don't think I've tried on full throttle, but it has died on both low, mid and high (though not full) throttle. So far, the only tuning I've done is with the high speed needle. I got it rich enough where it was burbling quite a bit, but it still died when I rolled inverted.

The guys at my club seemed convinced that I shouldn't touch the low speed needle since it's dying even when I'm above half throttle. Did you lean or richen your low speed needle? Right now the engine starts very easily, idles great, and transitions really good, so I'm a bit hesitant to touch the low speed needle.

Marc
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