futura127

My Feedback: (57)

Ok so I have a new DLE55 on a GP Pitts. I have 4 flights on it. First on went uneventful, second one the fuel line in the tank fell off, fixed that and third flight was good. Today I fly for 5 minutes engine running perfectly then all of a sudden it starts to want to cut out going vertical, then even in level flight and it flames out and safe landing. I go over and touch the motor and its is hot and not only that the aluminum spinner is really hot. I also richened it up 1/8 turn on the HS needle before. Any thoughts?

Sam-E

Lean...

w8ye

My Feedback: (16)

I would get rid of the DLE spark plug first

You had better check your fuel plumbing again?

futura127

My Feedback: (57)

All I run is NGK plugs. I through away the DLE upon receipt of them. I will pull the tank out again and check. I am using a three line system but the one line is just for filling. Everything was assembled new but I am guessing it is possible that the pickup line came off again within the tank.; I have never had these problems before with the nitro lines ever. I guess if it is off this time I need to wire it on. This sucks because just as I am putting this plane through my paces it starts. Hope that this is all that it is. I may check the needle setting too against what they should be from the factory but it does run good for the first 5-7 minutes.

Joe

av8tor1977

My Feedback: (6)

I use fuel line barbs AND tie my fuel lines on with safety wire as well. (Small plastic tywraps work ok too.) The gas makes most fuel lines swell, and then they slide off the tubing. Or cause an air leak that will drive you "batty" trying to tune out...

AV8TOR

apalsson

My Feedback: (1)

Joe,

Before you attach the fuel pickup line in the tank, slightly flare the end of the brass tubing. You can smoothen any sharp edges with a fine file or sandpaper.
Then push the line over the flared end and tie it off with a tiewrap.
Another method is to wrap a couple of turns of thin wire around the end of the tube and solder it on.
Also tie the clunk with a tiewrap.

Tygon lines have a habit of softening when submerged in the gas and can slip off unless some measures are taken

futura127

My Feedback: (57)

I think you are all correct on the fuel lines. I check the needle settings and they are correct from the factory. I think that for the first 5-7 minutes of flight there is enough fuel in there to make sure it is always getting fuel but if the line is off once it reaches that point then it starts sucking air. I will let you know what I find out tonight or tomorrow.

Tired Old Man

My Feedback: (1)

Once again for all to read. Disregard any needle positions established by a factory for they are-USELESS, mean nothing, and do nothing to establish a state of tune. The correct needle settings are, and always have been, the ones that permit your engine to run correctly for the fuel used, the oil and oil ratio used, the elevation, the ambient outside temperature, the relative humidity, the type and size of prop used, the airframe design and weight, and how you intend to fly the engine. Change any of those factors and plan on the possible need to tune your engine.

Not one of those factors can be established at a factory, nor should they be. You don't know if the carb was assembled with any particular number of needle turns specified in the assembly work instructions. Instead, many of you put blind faith in a factory setting up your engine for you before it is even shipped from the point of manufacturer. What's astounding, and also incomprehensible, is that most if not all of you will tweak the needle on a glow engine before every flight using one. Gas engines should be shipped with the needles removed to force people to initiate tuning activities.

If an engine is running hot one or both of two things is wrong. It's been tuned badly and/or there is not enough cooling air flow to and through the engine. Of course that discounts someone failing to mix oil in the gas. Prop size is a non issue if it's sized in a very wide range from ideal because engine tuning and airflow compensate for that.

To summarize in three words: Tune your engines.

Bass1

It's been pretty dang hot here on the east coast as of late. Do you have adequate cooling for your engine?

pe reivers

For a test, tune the engine rich with the high needle, then see if it leans out in flight. If it does, the engine has severe lack of cooling. Well cooled, the engine will keept it's tune throughout the flight, provided tank and carb setup is OK. Does the carb draw cool air, or must it try to get by with the hot in cowl air?

The Ghost

The problem is with the fuel system not the engine. A few questions, What type of tank setup?, What type of pickup in the tank?
No matter how much foam or insulation you have around the tank the vibration on the gassers will make the fuel foam, you will reguire a filter/pickup as fitted to ALL weed eaters/chainsaws to correct this, this will fix 99% of all fuel problems. Walbro make a great one.

You will need to run it slightly rich untill you have run around 1 gallon of fuel through the motor as they take some time to runin.
As has been stated, replace the DLE plug with an NGK this is done by the importer down here.

Cheers

apalsson

My Feedback: (1)

How far from Factory Settings do you suggest we turn the low needle?

pe reivers

as  far as needed perhaps? Ari, you know better!

futura127

My Feedback: (57)

I am running the OS bubble less clunk like I run in all of my tanks. The fuel tank is a three line system and it is the stock tank that came with the GP Pitts S-2. I really suspect that the line has come off inside the tank. I have a a flairing tool that I can flair 1/8 tubing so I will do this tomorrow and wire everything on. As far as the tuning goes since I am new to gas how does it differ from glow? It is easy to tune glow but gas seems to be a different animal. I have good ventilation into the cowl and my buddy has the same motor in a GP Ultimate and his engine is a cool as can be after the flight so I really am suspect to the plumbing. Like I said I will let you know tomorrow when I yank that tank.

futura127

My Feedback: (57)

Is that filter/clunk available at the local level?

aussiesteve

I am sure the person who posted those didn't mean those statements quite how they read but if you are getting fuel foaming in Gas that badly and that regularly, I would be changing my fuel supply and / or oil used. Or if you are getting that much vibration, Either learn how to tune an engine or change the brand of engine you are using before it breaks your airframe.

For the running rich statement, that is not quite right. richen it up by a maximum drop of 200 rpm by all means but running a gasser rich does it no good whatsoever, even when running in.

Some increase the oil content of the fuel when running in. Such as they run it at 40:1 instead of 50:1 (for many of the commonly used synthetics) however even running too much oil (for a particular brand) can lead to problems. (Try running the Mobil 2T for example at 25:1, your engine will run like a dog for sure but at 40:1 it runs fine and the oil works well at that).


For the factory settings? - depends on which oil is being used and how much of it is used

apalsson

My Feedback: (1)

Joe,

You don't even need a flaring press - if you have one, great. I don't have one and normally just use needle-nose pliers.

In regards to tuning, there are dozens of threads on the subject on this site but this document covers it well:
http://www.modelaviation.com.au/manu...break%20in.pdf

Sorry to link to my own site

futura127

My Feedback: (57)

What Walbro Filter/clunk would be used for a 55cc motor. That number above said good up to 30cc!

apalsson

My Feedback: (1)

Mate, your clunk will do fine to weed out any running issues.
It's "nice" to have the Walbro felt clunk but not essential.
I personally only have them in some of my planes. I use the stock clunk that came with the tank in many of the others and with no ill effect

tony0707

HI
THE N/V adjustments on the gas engines are 1/16 turn-not 1/8 turn like on glo engines you were running lean to get that hot

futura127

My Feedback: (57)

I didn't lean it out prior to running it I richened by 1/8

Tired Old Man

My Feedback: (1)

I'll be over in your neighborhood in a couple weeks.

Tired Old Man

My Feedback: (1)

Same as the one in the picture. Don't believe that 30cc limit number. It's good to above 150cc.

willig10

If you are running a 3 line system and the clunk fell off. I have a couple of questions.

After you fueled up did you see the fuel running out your vent line? Are you sure that during your routine that the vent line did not contact the muffler and seal itself closed? If it did the engine will go lean and start collapsing the fuel tank. It is possible that the clunk tygon tubing shrunk as well and allowed the clunk to fall off.

It is always a good idea to safety wire or use tye wraps for your fuel connections. I had this exact scenario happen to me on my maiden last year. The tygon tubing contacted the muffler and sealed itself closed. Upon landing the engine was of course hot and spinner as well, You would be amazed at how small a fuel tank can get under vacuum.

Check your lines and then recheck you needles. I have my DLE-55 running a tad rich on idle. You can see smoke at idle. When going from idle to full throttle I have my high end adjusted to where it will transition from idle to high speed with no hesitation and no lag. I like mine to be just a little rich during the hot summer here in Texas but not so rich where performance is affected.

Good luck and keep us posted of your findings.

Regards
GlennWilliams

Tired Old Man

My Feedback: (1)

So was it not even leaner to begin with? You missed my earlier points. The base needle positions on most Walbro carbs is 1 1/2 turns open. That will get the engine started. Everything after that is tuning since the engine is not in any particular state of tune when you get it.

Visit the link to Ari's site. Worst you can do is peak the high AND the low. From that point the low needle can only go richer to hit happiness. If the high is peaked it's where it needs to be. Go slow, and do it small. Those 1/2 turns you did in glow will kill you with gas. Once correctly tuned, 3/8 of a turn on a high needle will often shut a gasser down.

Once you learn the very minor differences in the way glow and gas tune you'll hate glow because gas is easier and doesn't change on a flight to flight basis like glow often does. It's normal to not touch the needles on a gasser for a year or more after it was correctly tuned.