Thats unusual, most of the time you tweak gas needles very gently, 1/8 turn at a time.

As an FYI, running a gas engine rich does nothing to contribute to the break in or that like nitro engines.

But running them rich does do a very nice job of carboning them up. Glow engines don't carbon up much due to the type of fuel and the combustion temps. They sometimes get varnished up, but that's a different issue usually caused by castor oil. Gas engines burn much hotter, and a rich mixture will carbon one up fairly quickly.

AV8TOR

On the bold, I'm sorry, that's a stretch for me. Not if you're running a quality oil. That may be true on a lawn mower or a leaf blower running garbage oil, but an engine running on the rich side that's making enough power to fly, carboning up to the point even sport flying performance is affected by it? That would be something I'd have to see to believe.

well easy done, open your needles up run for a few hours, then look inside the head.
No better test than one done by yourself, let us know how you go.

Been there, frequently. No damage. That's my point?

Maybe we're talking different conditions though? To me, a "carboned up" engine is very likely going to have a stuck ring and heavy ash deposits on the top of the piston and head? Noticeable carbon build up on it's spark plug (not just black), with a history of fouled plugs? Carboned up to the degree the performance of the engine is degraded?

When I think "rich engine", I'm not talking slobbery rich to the point it's missing badly trying to clear itself out on it's entire take off run and while at cruise speeds. I'm talking about an engine I would fly without hesitation. The rich engine I'm talking about is one that might be burbling in mid range, rpm set rich of max when set on the ground, unsteady idle, but good response? Mine are run this way frequently (especially when the weather has taken a turn to the warmer) - and there is no carbon build up. That's one of the bigger reasons I run a quality oil? Yes, oil needs to lube and cool, but it can't be causing/allowing carbon buildup either? -Al

Well, I've seen it, and with name brand oils too. On motorcycles, ultralight airplanes, yard equipment, and model airplanes. Carboned up rings, stuck rings, carboned up pistons, exhaust ports. I recently took a friends Super Tiger .90 that had been running on gas apart, and I couldn't believe how carboned up it was. And it only had a few gallons through it, running just rich enough to hear an occasional burble....

In the study in the attached .pdf file, the engines were adjusted to proper mixture/egt temps, and look at the carbon....

AV8TOR

hi
look inside carburator for dirt on the screen take hi+lo needles out blow air inside install them back
tune the engine it will be fine

ilan

I've been reading the thread regarding DLE 30 engine problems and it sounds like you guys may know what you're talking about. I could sure use some help with mine. Problem I have is that the plane will be flying around just fine and the engine quits. Seems the plane has made more dead stick landings than with the engine running. The engine is mounted upright in an Ultra-Sport 1000. I like to fly pattern sort of maneuvers and so I tend to use the throttle alot. The thing quits at something less than full throttle when the plane is exiting downhill. You can hear it falter or hesitate and then it won't throttle upit just quits. As a clue to what may be wrong, the engine burbles briefly when doing an axial roll. I don't know whether this means maybe the engine is too rich or too lean, let alone whether it is the high speed or the low speed needle that might need adjusting. The engine has had a couple of gallons of gas run through it. Ignition battery is 6 volt 2000 mAh with voltage regulator. I've switched plugs back and forth between the one that came with it and the NGK CM6. It quits with both of them. Examining the plug, it appears to me to be more black than brown. I've been flying glow for over 50 years and have to admit I'm a real novice when it comes to gas. I'm sure open for suggestions if anyone would like to respond.

I have only been runnig petrol/gas for a year or so, which makes me a newcomer as well, but it sounds like you are lean on the top end, the low mix screw is working all the way through the rpm range and the high kicks in at around 1/2 (I think) You have a tuning problem for sure, my dle's have never dead sticked at all, use a plug in rcexel tachometer when you are tuning, I found the optical ones are inaccurate
Have a look at the last post (27) on the sticky http://www.rcuniverse.com/forum/m_86...mpage_2/tm.htm
Make sure you use a ngk or rcexel cm6 plug, the dle one is useless
Let us know how you go.

Could be a problem with the clunk line in the tank. If tygon, it may have gone stiff, etc.

Rich engines don't quit, especially right out of the blue like you're describing. If going richer on the needle won't help/fix it, you'll have to go through the rest of the fuel system? Regarding having the clunk coming out of the fuel on the down line, if everything else is OK, the engine will run for a good 10 seconds or so (at least?) on just the fuel in the line and carb?

Regarding which needle is causing the problem, if it's flying fine at higher throttle settings, I'd start with the LS needle?

Lets get back to the plug for a minute.

Take the stock plug, stick it on a bench and smash it with a hammer, discard the pieces.

Put the NGK in and check the gap, it should be the thickness of an exacto blade. If it still does it that will rule out the plug.

How is the transition from idle to full throttle when the engine is warmed up?

Thanks, guys, for all your input. You've certainly given me some good information. From your comments, it sounds to me like my problems have to do with tuning; the engine carb settings may be too lean. First of all, I'll replace the plug with a new NGK CM6. Then I'll open the low end needle a bit and see what happens. If it quits after that, I'll richen the high end slightly. It's going to be a few days before I'm able to get out to the flying field to see what happens, and after I find out, you'll hear back from me.

Regarding the engine quitting, the weather here has been either too cold or too windy or both to do any flying. Will let you know after I get a chance to fly it again.