Born2Fly

My Feedback: (21)

Hi,

I have my first gas engine DA-50 mounted in my PAU Extra. I am on my 6th gallon and I I was adjusting needles for the last 10 flights. Here is my problems; First, before starting the engine first time in the day I chock it and it always cause flooding. Second, after it sits for some time (approx. 10 min ) I am able to start it but my idle is too high so I need to use trim on the radio to bring it down. After I fly it usually dies on the ground after landing. No problems during flight, just occasionally burps at the mid range, but transition is pretty good. After that it usually starts with the first flip of the prop but idle need to be trimmed before every other flight that day. I am running 23x8 Bolly with 100:1 Ashles synthetic. By the way I also have carb plate installed. I am at sea level. As I said before I was adjusting my low needle mostly for the last 10 flight so I can have somewhat reliable idle. So Low needle is right now at hair less then 1 turn out and the High at 1 ½ I still feel that engine run rich but I am a bit scared to lean it more. Is it normal to have this needle positions? Also,is it safe to go leaner? Or should I make it richer? I am kinda lost right now so please help. Thank you in advance.

nonstoprc

My Feedback: (90)

I never heard of "100:1 Ashles synthetic", you mean 100:1 amsoil and more importantly the oil is rated for 100:1? I used to run 100:1 amsoil @ sea level and the low needle is 1.5 turns out. I eventually switched to Pennzoil Air cooled @ 32:1 for extra protection and the low is 1.5-1.75 turns out.

Flooding while choking usually is caused by too many flips without turn on the ignition. Unstable idle can be caused by a leaking carb block. If the high RPM drops badly (e.g., during vertical up line) or the engine is too hot to touch after landing, it is too lean.

I would think it is a good idea to make sure the oil ratio is OK and then check the leak. Usually tighten the two red alum bolts that hold the carb to the engine back a little bit is sufficient.

bubbagates

My Feedback: (32)

It definitely sounds like you are out of tune. I would say you had an air leak but since you are flooding it during choking it appears to be OK leak wise, though it's still possible since you did not mention the normal amount of flips for choking.

So lets start back at the beginning and retune it. You will need a tach for this and forget about where the needles are set. You could go up one hundred feet in altitude and your needles will be different than everyone elses. You always tune for your location. I see this a lot and experience it when traveling to different locations for IMAC meets.

So lets open both needles 2 full turns and start the engine. Now start leaning the high needle to max rpm, turn it no more the 1/8 of a turn at a time and never tune while the engine is running. So once you have max rpm, then richen it up so that it loses about 100 rpm, this compensates for altitude while flying.

Now let's lean the low needle, again, no more than 1/8 turn at a time until the engine will not transition to high rpm when opening the throttle quickly, then richen the needle 1/8th turn. You are now tuned

On the idle thing, are you using a plastic or thin carbon fiber rod. Both will change length when they warm up, thus changing you idle.

Also, make sure your oil mix is correct, to lean on the oil at 100:1 can cause the engine to do overheat quickly thus destroying it in pretty short order and also proper tuning is an absolute must at that lean of a mixture. Retuning after changing the oil mix is not uncommon.

Born2Fly

My Feedback: (21)

Thanks for reply. I think my explanation was not very clear. When I chock it first time it fires up after 3-5 flips, then I open chock and on the next couple of flips fuel start dripping from carb and it will not start until I wait 10 min. That’s why I think it might be too rich. However, I may be mistaken it is my first gasser. Another thing, I always thought that I should set low needle first and then set my high for max RPMs. I do not think I have an air leak somewhere because engine is running rich not the other way around. Air leak usually cause engine to be a leaner even with the needles set rich, but my over all flying up/down lines, inverted, knife edge are great. I am using the cable for my throttle. Any other thought. Should I start over with my settings and work from there. Thank you.

3d-aholic

My Feedback: (7)

Doesn't sound tuned...but its hard to believe that fuel drips out after only one choke flip run and 3 or more flips with the choke off. Are you sure your low end is one one screw out....?

Might be something wrong with your carb....

Born2Fly

My Feedback: (21)

That’s does not looks to me right either, but that what I am having right now. That is why I am posting here. Before my 4th gallon everything was working fine. Is it possible brake the carburetor? I have no crashes and may be one soft prop strike. And yes double check yesterday low needle is less then 1 turn out.

IShootSharpStix

My Feedback: (4)

Why not just ask the people most qualified to help you???
http://www.desertaircraft.com/page.php?Page=Contact
Phone: 520.722.0607

nonstoprc

My Feedback: (90)

Set the idle needle at 1 turn out can restrict the flow of fuel to the carb too much, and makes it difficult to start. But I am still puzzled why even at 1 turn out it is rich. May consider try gas with high oil content (e.g., 40:1) as suggested on DA50's manual.

Give DA a call is also a good idea.

bob_nj

My Feedback: (62)

Could be a million things.
A metering arm spring that is too high can cause the hard start/rich condition.
Pop off pressure could be off a little.

How new or old is the engine, and do you know it's history?

Born2Fly

My Feedback: (21)

Thank you for all replies. Here is some additional info. I called DA and they told me that 1 turn out is too lean. And you was right, it is restrict fuel flow to the engine. So tech told me that right now I should have 2 turns out on high and 1 and ¾ on the low. So I did some adjustments earlier today. When I try what DA suggest idle was terrible and the engine quits after some time. Transition was was….well it was no transition. So I have to lean it a little bit. Engine is running much cooler now, idle is mostly reliable but it burbs a lot on the mid range. Transition is not great but acceptable. I end up with following settings; high 1 ¾ and low is 1 ½ turns out.. It swing 23x8 bolly at 6300 RPMs. I hope it’s a good RPMs for this prop. Re: engine; I bought it new and I did all the brake-in according to DA manual. One more thing, right now after long and slow knife edge it seems like engine gain some RPMs when going to the level flight. I was reading something about it but do not remember what exactly it means. Also, when I go from high to low it is take some time for engine to settle down. I mean it drops RPMs to 2400 then is slowly goes down and stays at 1700. My personal feeling that I should have it lean it a little more but I afraid I will end up with the same settings I have before.

Steve

My Feedback: (54)

Born2fly,
I was having issues with mine also. I've got my DA in a PAU Extra also. I checked my filter screen inside the carb and it was getting plugged. I also used some RTV on the carb gasket because I think I was getting an air leak. I pulled both needles out and cleaned them. They have some kind of thread lock on them that may have been getting into the ports. I tried running my low needle one turn open and the DA 50 doesn't like that. I'm now at 1.5 turns open and it starts a lot better. Now my engine has been running like I thought it was supposed to. I'm pleased with it and its been performing flawless. I've also done some mods to the carb that are in my 330 build thread that you have seen. Hope this helps.