Idle problems
 

I have a crrc26cc that has about 4 hours on it. I've been getting it ready for its first flight, I thought I had it tuned, had a good slow idle and smooth transition. but i went out and started it today and it would not idle down. I had to trim the servo up about 3/4 of the way just ot keep the engine running. Any thoughts what might of happened?

RE: Idle problems
 

Four hours of bench running, that's a lot of wasted flying time. Hopefully you never hurt the engine during your bench runs, which can happen. Check to make sure that your fuels line is clear, have no holes and has airtight connections as you could be sucking air from somewhere. Try retuning the engine from scratch and see how it behaves.

Karol

RE: Idle problems
 

Ok. This is what I have going on now, I can run the engine to WOT and when I bring it down to idle some times it will stay at a fast idle for maybe a 20 seconds and sometimes longer before falling to a slow Idle. I tried adjusting the low end but I'm not sure what to really do. The transition is good and the high end is good. Is this a tuning problem or maybe an air leak? or something else. Thanks for any help.

RE: Idle problems
 

It sounds just a tad rich on the low speed needle.Try turning it in very little.

RE: Idle problems
 

Most times when your engine won't decelerate (hangs up at a higher rpm for a few seconds)before settling down to an idle, means that the low needle is a bit lean. Properly tuning a carb is not rocket science and if done correctly the engine will thank you by performing well. For finding out exactly how your carb works and how to tune it visit the RCGF engines web site and under the heading 'Articles' you will find all the info you need to do it correctly or use the Search feature on this forum and do a search on Tuning a Walbro carb, and keep us posted on how things turn out.

Karol

RE: Idle problems
 

Sometimes this same symptom can be due to having a rich idle. When someone sets the idle speed based on a rich idle mixture, when it is revved up the engine clears out the excess fuel that has accumulated. Then it idles faster for a bit until the rich idle mixture causes it to slow down again.

In any case, as mentioned, the engine should be tuned properly.

AV8TOR