Some os motors have indeed this problem. Try silicon tube over the needle
> with these motors but the symptoms sound like something is loose in the
> region and air is leaking past it into the motor making the mixture vary.
> Peter Wales in Sunny Orlando
> > I hope someone can offer some advice. I'm pulling my hair out
> > trying to get this engine up and running at a reliably consistent
> > idle.
> > This is the LX version of the OS61 engine. It has a high range
> > valve setting and a low range idle***setting. No mid range setting.
> > Symptoms:
> > At factory settings, the idling is really bad. I have to open the
> > throttle so much that the clutch engages. Lowering the throttle,
> > the engine dies.
> > The only way I'm getting this engine to idle somewhat reasonably is
> > to richen the idle mixture out about 1/4 to 1/2 turn. The engine
> > will idle somewhat OK at this setting, but what happens is that it
> > will start revving up and down (as though it's getting intermittently
> > leaned out). It seems to increasingly lean while running and if I try
> > lowering the throttle trim it dies. When I pull the glow plug out
> > at this idle setting, the engine RPM drops a bit which I think indicates
> > it's too rich, but if I lean the idle mixture it just gets worse than
> > factory setting. Another thing is that when I do have it idling,
> > it seems to be very sensitive to movement -- RPMs fluctuate when I
> > lift the heli up to set it down somewhere else. Bottom line: best I
> > can seem to do is keep it idling for a minute or 2 before it ends up
> > dying.
> > Debugging:
> > There really seems to be some kind of fuel flow problem somewhere.
> > I've checked the lines for leaks, removed filters, checked tank and
> > clunk line. I'm using CoolPower 15%. This stuff runs just great
> > in my Raptor with OS32X engine. I've pretty much run out of things
> > to try. Could it be something in the pipe?
> > Also, this is the second LX engine I've tried in it. The first had
> > similar problems, but I did have it running much better with a
> > richened idle mix. So, I really think it's not an engine problem
> > but something in the fuel setup or something else.
> > Anyone think of something else to try? I'm pretty much out of ideas.