Skinny Bob

My Feedback: (12)

I need some help, I am running a DLE 20 that ran just fine for awhile, now I can't get it to idle below about 2000 rpm. I have tried all the adjustments at no results. It will jump to full rpm with no problem. Will the DLE electronic ignition cause this, I have ruled this out as it will go to full rpm with no problem. My next guess is the carb, should I tare it down and check for a dirty screen etc.

Appreciate any help

Thanks
Bob

ahicks

My Feedback: (2)

The screw that holds the throttle butterfly in place on the throttle shaft - they will occasionally loosen letting the butterfly plate slide off center. If that happens, idle speed will be erratic.

Skinny Bob

My Feedback: (12)

Thanks for your input, I did read about that while searching the forum. I will pull the carb and check it out.

Bob

Skinny Bob

My Feedback: (12)

ahicks, the throttle plate screw was not loose, however, the fuel inlet screen had some slimy substance on it, which I also read about on this forum. Where does this slime come from and what can one do to prevent it?

Thanks
Bob

captinjohn

Tip....make sure you use a thread locker on the throttle plate screw........ Capt,n

ahicks

My Feedback: (2)

Sorry Bob, I think I misunderstood your post. You were talking about rough running, I was talking about idle speed, or more specifically, it would not slow down any further?

That clear stuff comes out of the blue. An evil prank created by Gremlins... Doesn't happen to me often enough to try to do anything to prevent it. I think filters create more trouble than they're worth. Run one in the gas can, another for a clunk, that's it.

Indiomike

My Feedback: (5)

I seem to recall that Jodi once said if you put a different brand of oil into a container that still has a bit of the other brand oil in it, it may form a slimy substance. So, if you recently changed the oil brand, that may be where the slime came from. Just a possibility.

Mike

ahicks

My Feedback: (2)

Hadn't heard that. Will try to remember it the next time I end up picking that gook out of a filter.

RJConnet

I have also heard what Mike said about switching oils, particularly when switching from a Dino to a synthetic oil (or vice-versa). Any remnants of the original oil left in the fuel tank, fuel lines, or carburater can mix with the new fuel and cause this clear goop to precipitate out and clog the screen or any filters. Some times it's no problem but other times it can be a real headache.........RJ

dubs1946

Hi there is a few guys in our club who have suffered from the dreaded "SLIMY STUFF" there has been some discussion between us and have arrived at no certain cause.
This has killed a couple of our club members aircraft so it should not be taken lightly. This has caused me two flame outs as well.
The suggestions were.
The petrol is having an effect on the fuel tubing Chinese or otherwise. Leaving the residue in the small carb filter
The petrol is having an effect on your plastic or otherwise fuel container. Leaving the residue in the carb filter.
There is a bacteria in the fuel leaving the residue in the carb filter.
The petrol is having an effect on the aircraft's fuel tank or the cable ties in the tank to hold the clunk etc. on, and leaving the residue in the carb filter.
Any more suggestions?
What i do know is i take a very good look at the small carb filter on a regular basis.
Dave.

ahicks

My Feedback: (2)

dubs, so what you are saying is your club brethren don't know either...

I wouldn't suggest being too paranoid about that slime. But if you run into a lean condition that doesn't respond using your needle valves, that's a darn good place to look first! Probably goes without saying that if you're in there for any other reason, giving it a quick look would be part of a good plan as well. Doesn't take much to get to it....

dubs1946

Yes thats how i picked it up a couple of times, if your engine seems to run lean for no apparent reason and a richen up on the needles does little then its the dreaded GOOP gremlin in the carb filter.
Don,t take the filter out as the fuel passages are so small that they will block up.
No one seems to have a definite answer to the GOOP , where it comes from what causes it etc.
There was one mention that it only occurs on little used engines that have been stored ie. like your best scale aircraft bought out for a scale contest, and not in engines that have regular use, but who knows. Also i filter 4 times before it gets to the carb. Some of my aircraft have well buried engines and its a days work to get them in and out.
Dave.