Joe1199

Hi,

im having trouble with my DLE 30 mounted in an inverza 33, it's my first gas engine after years of glow so go easy on me!

I can get the engine primed, choked and started no problem at all, in fact it is probably the easiest engine I've ever had to get going, then the problems start!

it will idle really well but above half throttle when running on the high speed needle it misses intermittently and will not reach peak rpm, no matter what the needle is set too.

i removed the plug and found the gap was about 0.40", I lowered this to about 0.20" which made it run worse!

i added an extension to the high speed needle screw so I could adjust it easier, do gas engines react the same to changes as glow?

im using a 4.8v 2200mah nimh for ignition with a on board indicator which shows no voltage drop at high rpms

Could an oil rich mixture cause rough running? I'm using about 25:1 which I think could be too much oil

im going to try a new plug but wandered if anyone has had similar problems? As I said it's my first gas engine, I managed to get a short flight with it last weekend so I was really disappointed I couldn't tune out the rough running to get it going properly

thanks for any help

joe

Truckracer

My Feedback: (19)

Yes, 25:1 is probably more oil than needed but the engine should still run OK at that mixture. Yes too, a gas engine reacts to needle settings just like a glo engine does. When rich it has that distinct 4 stroking, not firing every time sound which smoothes out as the needle is turned leaner. When too lean though a gas engine will once again start to miss and run rough where a glo engine will tend to just sag.

Is your engine a new one or one that has some time on it? In other words, does it have any history of running OK in the past or is it an unknown? How old is the engine? If timing is too far advanced and some DLE30's had this problem in the past, it can run rough at high speeds regardless of how the HS needle is set. A wide plug gap can minimize this effect but not eliminate it. Give us a bit more to go on and maybe a course of action can come from that.

Joe1199

Thanks for your reply, the engine is used and came with the model, I did however install it and all the ignition system etc, from that I can assume it ran ok at some point.
It ran ok last weekend, well enough to attempt a maiden, it ran better on the ground than in the air but due to the weather I did a few circuits and that was it.
During the week I removed the high speed needle and attached an extension to it so could tune it with the cowl on, I reset to 1.5-2 turns out but it wouldn't run without either a misfire type sound or very rough today, nothing else has changed.

One thing I did notice was the hobbyking nimh I'm using has quite a small gauge wire, it's a 2200 receiver pack so surely couldn't draw too much on this ignition?

Thanks

Truckracer

My Feedback: (19)

If the engine ran better on the ground than it did in the air, you may have an air pressure issue in the cowl causing the regulator part of the carb to richen the engine in flight. Make sure you have plenty of air exit area in the cowl and you may benefit by adding a baffle in the front of the cowl to restrict the airflow to just the area in front of the cylinder. Large round cowls are known to cause rough running if not baffled in this way. In some cases it may be necessary to install an equalizer line from the regulator cover back into the fuselage where air pressures are more stable. These are many times connected to a pill bottle or balsa box with a tiny hole to limit the effects of air pressure changes. Much has been written about this so do some searches and you should find way more info than you may want to know.

You may benefit by checking the engine's timing. The sticky at the top of this page disussing Rcexl ignition sensors has quite a bit of content about timing. You can learn quite a bit from that thread. There are many other threads that also discuss timing. Your engine uses the RCexl igntion so any thread discussing timing and that igntion will apply to your 30.

I dislike adding extensions to gas carburetor needle valves! The extensions can vibrate which can cause the needle valve to wear the carb body threads over time .... then you won't be able to keep a needle setting. Unlike glo engines, gas carbs are pretty much a set and forget thing so once you get past the inconvenience of setting the needle valve early on, once set you won't have to mess with them much if at all for a long time to come.

Joe1199

After reading the sticky thread on this page I removed the plug cap and when I turn the engine over there is clearly a spark jumping between the silicone boot and the outer cap, there isn't much detail on the effects this would have on running but can't be good??

Truckracer

My Feedback: (19)

As you look up into the cap, if the spark you see jumping is way up inside the silicone boot, there is a problem with the insulation breaking down which probably was caused by damage, see below. If the spark is jumping around the bottom of the visible silicone insulation, that is normal and just shows that you have a nice strong spark.

On a used engine, if the cap ever came into contact with the ground, such as during a bad landing, the insulation can be damaged. It takes a very minor impact to damage the insulation. If the insulation is damaged, you need to replace the cap and again there are quite a few instructional threads on how to do this. Certainly this could affect how the engine runs. You could also replace the whole ignition box but this probably isn't necessary.

ahicks

My Feedback: (2)

Turning the engine over with power to the ign. module and no plug installed is not a good plan. There is going to be a spark created, (as a rule) and if it can't find a place to ground where it's supposed to, it's going to go look for some place else. Unfortunately, that can often be the pickup, made with components that are not going to like that spark much at all. They're frequently blown.

That silicone insert in that plug boot is easily damaged in a rough/nose over landing, that can cause a spark leak to the metal boot jacket, even if there is no apparent damage to the boot externally. This can lead to a no start/hard start, or erratic running. Unpredictable spark would be the thought. To complicate further, a plug inserted in one of these damaged boots will often spark just fine when not installed in the head - only to break down totally when installed and under compression. Not sure if any of this applies here, but you should have the potential for this scenario in mind when things start going badly after a less than graceful landing/arrival. A lot of us flying gas frequently keep an extra ignition in stock, just cuz....

I would encourage you to remove the cowl and leave it off for the next few flights. You eliminate the potential for over heating, as well as the pressure differential thing, and the carb is MUCH easier to get to for quick adjustments. This will often let you try adjusting one way, making it better or worse, and moving on from there. Once you have it dialed in and some confidence built up, then install the cowl, knowing full well if there are problems at that point - they're cowl induced.

Truckracer

My Feedback: (19)

There might be a problem flying the Inverza w/o the cowl as that cowl is huge and flying with it off could affect the CG to a point of causing problems. I would carefully check the CG with the cowl removed before I would fly it that way. In most cases I 100% agree that flying with the cowl off is a good troubleshooting method and it still can be in this case. I'd just use a bit of caution to make sure the CG is within range so there are no additional surprises.

ahicks

My Feedback: (2)

If your flying style lends itself to enjoying your flying low and slow (3D tendencies), you might enjoy flying with the CG back a little from suggested....

Good call on TR's part though. You should know about where your CG is anyway. In the case of this plane, and 99% of the suggested CG's I've ever run across, if you're close (within 1/2"), I'm sure you'll be fine. Not knowing how you're set up with the cowl on makes the CG warning something you really should consider. Especially if you're already back 1" from suggested CG with cowl on. -Al

kmeyers

Joe
The first thing I would check is the internal metal filter screen in the pump side of the carb. Often the problems your describing are created by low fuel delivery.
The screen is easy to remove, clean and replace if your careful. Flatten it blow it clean with carb cleaner and push it back in to the bottom. If you see any debris in there at all you may have found your problem. If it is all crapped up you did find your problem.

microdon2

My Feedback: (47)

I have a used DLE30 - have owned it for over a year and am just now starting to run it. The problem is it is very hard to start - it occasionally backfires and sometimes does not start at all. I have re-built the carb, re-set the needle setting to default, and still have the problems (my arm was sore last week from so much prop flipping!) With the plug cap off and the plug inserted I'm getting spark, just fine. When I DO get it running it runs great at mid-high RPM's - but when I bring it down to idle it seems to idle fine for 10 seconds and then dies and then I can't get it restarted. But something that ahicks (HEY, Ahicks!) just said tells me that there may be a problem with the boot insulation (though I don't SEE any crack in it.) So I'm now thinking it's either something electrical \ no spark, or the reed valves are not seating flat. Last night I rigged up a completely different electrical system on this plane \ engine (from new spark plug, Halls sensor, EI, IBEC, power switch, and battery) and will try starting it tonight when I get home. If it's not that then I'm guessing it's the reed valve. Question - would the exact location of the Hall sensor make much of a difference? I have it positioned in the middle of the pre-drilled holes in the crankcase, so I'd think that should be good. Any advice is welcome. I GOTTA get this engine running! (I will post my findings tomorrow) (btw - I also have a DLE 20, 30, and 35 - all running)

Thanks.

kmeyers

If you have the plug out and in the boot you might as well throw a degree wheel on there and check the timing. CCW 28*-30* BTDC.
Sounds lean on low end too.

rcguy59

My Feedback: (8)

Sounds just like a bad ignition battery. At low rpm, it's got enough capacity to keep the fire lit, but it can't hold the voltage high enough to prevent missing at high rpm. Load-check the battery.

Joe1199

Thanks everyone for the replies, I've ordered a new plug cap, ignition battery with heavy duty leads and a new plug, I've taken off the cowl and I'm going to clean the carb, hopefully that will make some difference!
The reason I ran the engine at the field with the cowl on was because of the CG issue so I'm going to re balance with it off to make sure

I'll try and get it going in the next few days!

Thanks

microdon2

My Feedback: (47)

So the engine runs great with the new electronics. (and the Halls sensor was set at 28 deg, btw). But the problem is it takes forever to pull fuel when I'm trying to flip-start it. So I looked at everything again - the carb, the tank, the lines. Now, with choke closed and throttle WOT, it won't pull at all (when I flip the prop by hand). With my other DLE 30 and 35 it usually takes 10 flips the first time for a "pop", then another 5 with the choke open to start. Now - with this 30 - it's not pulling at ALL when I flip the prop by hand. I then tried a starting and 22 volts of power turning that spinner QUITE fast, and it finally pulled fuel, and quickly, to the carb. A few more hand flips and it started, and seems to be running fine now (both needles now set to about 1.5 turns). But I should not have to rely on a starter motor. So - question - why am I not pulling fuel normally? Could the carb passages be dirty? If so, how do I clean those? Could the metering level not be high enough? (though I measured it with my Walbro gauge, and it looks correct).

Thanks.

ahicks

My Feedback: (2)

PM sent Microdon

microdon2

My Feedback: (47)

Tonight I will look at the throttle choke-plate and also re-pipe the tank. Seems like a pressure leak somewhere.

microdon2

My Feedback: (47)

I tested using a tank from another gasser and the DLE30 pulled fuel fine. So I installed a new tank, stopper, pipes, tubing, and it's now pulling normally. Will test again tonight, but do not anticipate problems.

microdon2

My Feedback: (47)

With the new tank and plumbing the DLE30 is now drawing gas normally, and the engine is running perfectly. Sounds like a beast! Ready to maiden this CG Sukhoi this weekend!

rcguy59

My Feedback: (8)

Just goes to show you, engine problems aren't always the engine. If it's anything like the 30cc Sukhoi ARF's that I got from ValleyView several years ago, you're gonna LOVE it.

All Day Dan

My Feedback: (5)

micro, What was wrong with the original tank set up? Dan.

ahicks

My Feedback: (2)

So it's not just me wondering the same thing! -Al

microdon2

My Feedback: (47)

A few things, probably cause I was trying to re-use old parts. The stopper was old and worn out, the tank was old and the tank throat was larger than it used to be, so the stopper did't really plug it, I used stopper plates with holes for 1/8" tubing, and mixed 1/8" tubing and 3/32" tube, and, possibly the cause, I'm thinking the tubing wasn't pushed on enough over the copper tube and barb, so there may have been an air leak there. So I just started from scratch, with new, correct parts. Seems to have worked.

All Day Dan

My Feedback: (5)

Thanks for the info. It's just one more thing we will have to watch. Dan.