OS .50 Hyper idle problem.

[furyevo]

My OS 50 Hyper has devoloped a problem with idling. When I start it, it barely wants to run. Transition and high end are great, but it idles low, and takes a bit to "clear out." It seems to be loading up, and any time I come back to idle it does the same thing, but messing with the idle needle does nothing. Is this a sign of trouble down the road?
I have changed the glow plug, checked fuel lines and clunk, seems no reason for this to happen, and I'm not great at engine tuning. Any ideas?

[Motions]

Are you sure your turning the right needle? I can't imagine it not doing anything. Try bumping your trim up some.

[furyevo]

Bumping up the trim only makes it run faster if it catches up. It's not that the low needle does nothing, it just doesn't stop the loading up.

[Motions]

Strange. Two more pieces of information... What plug and what exhaust are you using?

[furyevo]

OS #8 and a MP2. Now that I think about it, this started when my OS A5 finally burned out, and I put in the #8. This could be it. :roll:

[BarracudaHockey]

That engine runs fine on an 8

Do the pinch test, at idle pinch the fuel line close, see how long it takes to speed up.

[DebianDog]

I tell you what I no longer have an OS50 but that is (to me) the most challenging engine to keep running right. Put a pipe on the thing and it want to run the helicopter at 2200 RPMs.

[playfair]

Sound like it's time to pull and clean the needle and low end barrel.

[furyevo]

Ok, I put a brand new A5 in it, and the problem went away. It still runs the same top end, but idles better. For whatever reason, it likes the A5.