Looking for opinions to help me troubleshoot my engine issues. I have a DL50 that has run perfect for over 6gal. now until yesterday. I have not had to touch the needles for over 4gal. now-couldn't ask it to run better. Anyhow, yesterday I am running it up to get a tach reading and after about 6-7sec. @full throttle, it slows down and dies. I am puzzled so I start it up and it runs ok and proceed to fly. Engine runs good and I do some extended verticals to see if it sags any which it does not-never has. After a few minutes, I land to check fuel and do another takeoff @ full throttle. Plane begins climbing out and engine slows down and sputters/dies. Long story short, it will start easily, idle fine but when going to full, it will sputter and quit. If I advace throttle r e a l slow it will throttle up but spit/sputter and try and die. I didn't push it much since it was getting dark so this is where I am at.

I don't think that the tune would change-it has been at the current tune for a long time and nothing has been changed
Could it be a dirty carb screen??? I do use a felt clunk in the tank
I got new (2gal) gas in my can but I ran another engine the other day and it ran fine.
Reed issue?
Air leak...... I don't know and so I guess the engine will have to be pulled and start looking at the carb[:@]

Ignition battery was fully charged BTW.
I guess my first step is to play with the needles but I am doubting that this is the issue.

Thanks for any input on this situation!

It sounds to me like it could be lean.....and is overheating. I usually have to retune my engines in the fall.

Go with the retune and if that does not work I would take out the clunk , flush the tank and replace the clunk. It does not hurt to clean the carb , or at least check the screen to make sure its clean. How old are you fuel lines and have you ever changed them? Old fuel lines can get brittle or soft depending on the type of line you used. Could be as simple as a new spark plug too.

Andy

Fuel lines are 8months old, so is clunk. Plug is a NGK as suggested and has about 5gal. on it. I am thinking more a dirt issue or reeds but won't know for sure til later.

From your description it could be many things. Do a vacuum or pressure test on your fuel system, check the filter screen in the carb, but the intermitant nature you describe would lead me to ignition. Spark plug, a bad plug connection, frayed wire rubbing on something, sensor, maybe even module, etc.

Most likely a fuel issue (but not necessarily), but probably a dirt issue because the problem happened so suddenly.

Dirt in the carberator fuel screen "should" accumulate gradually, so a lean condition would come on gradually as well.
With so sudden of a problem, I'd just go ahead and pull the carb and disassemble, clean, and reassemble. Likely a piece of something in the needle opening itself.

Also check your gaskets and diaphragm for integrity. Air leaks would cause the same symptom, and about as quickly.

Bottom line; the problem is somewhere in the carb.

you wanted a opinion...I hope you are not using a 100-1 oil! If the engines goes lean...how much lube do you think is going to be left on cyl wall as the engine die,s from going lean. Think about that...not just you...whoever reads. Capt,n

2 gallons and never touched the needles... 4 more gallons after the first adjustment. Figure it might be broke in now?? Slows down and dies after a few seconds. Clearly got hot, but the reason? Lean, poor cooloing, or both.

Pennzoil @ 32:1 ever since day 1!!!

In reply to TOM, I started the plane up last night after getting home (approx 3hrs. after shutting down at flying field) so it was totally cool, engine did the same thing after a few seconds so I know it is not a cooling issue, plus, the setup (cowl opening etc. prop.) has not changed since day one.

During the flight, I did some LONG verticals and the engine did not sag at all.....

Confirmed by a recent experience that Jody helped me with, I'd never re-tune to solve a problem like that. If you are confident it was tuned well, and I bet it was, then start looking for the real problem. In my case it was crap in the screen...caused I think by Hayes neoprene. Not 100% sure what caused the crap in the sceen, but 100% sure it was crap in the carb screen that caused my woes (wouldn't transition, very high idle, wouldn't hit peak RPM's anymore, dead sticks). The screen is one of many things that could cause it. Could be the carb bolts loosened up and/or a gasket problem. As mentioned it could be ignition area too. That includes batt, switch, spark plug (doubtful), ignition module. Could be tank plumbing. Hope you're not using Hayes neoprene. This caused the same problem in my DL-50 and DLE-55. Was not the engines problem at all and Jody was very helpful.

No, using Tygon. I will pull the carb and see if it holds any clues...hopefully it will be something as simple as dirt in the screen!! Whatever the issue is, it came on suddenly yesterday-I've never had an experience like this before. Last time out (a week ago) it ran perfect.[sm=confused.gif]

You'd think with the felt clunk that there be no chance of dirt getting in the carb screen. Is this a two or three line tank setup?

Three line setup-one to carb, one to vent and one to fill. Fill line has a plug I use, vent does not[X(] but, theres still the issue of the felt clunk....could dirt/debris still get through that felt?????????

No "T's" anywhere in my fuel system.

Dirty screen is the culprit in most cases like that. Can happen very sudden, not only graduately. So, that's what I would check first, if you haven't done so by now.

Check the screen like noted..but if needed check for air leaks in the intake system. You may need to pressurize the crankcase & apply soapy water. It will bubble where the leak is. Capt,n[X(]

I have no personal experience with this but I have heard of two people that have had the felt fibers appear in their screen. One was (I think) RAM3500 here on RCU and another was a senior very good RC guy in my club. I mentioned this here recently and some seasoned gas engine guys said they never had that happen. When you get that screen out, look at it in the light. Mine was covered by a thin silt. And was very tough to get out 100%.

Nothing will get through the felt clunk but some felt clunks can shed small fibers that will plug up the screen. If the screen is properly in place there is no reason to disassemble the carb any further, anything that gets through the screen can go through the carb without causing a problem. Anything in the carb after the screen during original assembly would have caused the problem before now. When you check the screen you have to pull it out of the carb and hold it up to a light, make sure you can see through it clearly not just shadows. The screen can look totaly clean sitting in its hole in the carb yet be completely plugged up.

Well took the screen out last night and it was clogged prob. 60% with what appeared to be the fibers from my clunk amongst other little particals. Coudn't really tell until I held it up to a light-this of course after dropping it several times and losing it once for about 5min.[:@]. There was actually a small collection of stuff under the screen in the corners. So, cleaned it all good and put back together. Didn't get to fire it up cause it was late but will do so today and report back. Hopefully my prob. is now solved. Thanks for the help!

Jody said he used a felt clunk with a Final Filter just before the carb. So that's what I did the last time I re-did my two planes a few weeks ago. Then I'll just replace the felt clunk and final filter every year when I re-plumb the tanks.

Don't be surprised to hear your engine running awesome again. Mine both did after the screens were cleaned.

Also I wish I could get those screens back in the carbs like they were orignally. They get sort of bent up getting pulled out and I don't believe they seal around the edges as well. But hopefully the Final Filter will keep me from having to go back in there.

Those little white fibers will collect on the screen when you use a plain none filtered clunk also

It must be in the gasoline when you buy it?

I'm with ya here because I've had the exact same thing happen. I've always used the standard clunk and I found my screen completely plugged with fibers. Same with my nephew's DA50 and he doesn't use the fiber clunk either. I can't say for sure where it's coming from but I'm leaning towards the fuel or else the fiber stuff's in the tank when they are new. After cleaning my carb and putting in a kit with a brand new screen, I haven't had any more troubles and that's been a pretty long while back.

I always rinse my new tanks out with alcohol really well. Who knows what's in them when they are new.

I had the same problem but it was old tank fittings. Changed the fittings and added the hanger 9 pro fuel filter (HAN143) in line and added a fuel tank vent filter from Dons hobby shop. Found dirt was getting sucked into the tank from the vent so close to the ground in the prop wash. I also put the same in line filter on the fill line from my gas can to eliminate problems from there. Runs great like when I first dialed it in.