Why idle speed suddenly too high?
in 912 / 914 Technical Questions
11 years ago
Hello all.
Puzzling one this :dry: Today when starting my engine (912ULS 100HP), I noticed that the choke knob was very hard to pull out, as if something was jamming the cable.
I pulled harder, and it did come out but was very stiff. I cycled the choke a few times, and it became easier to move in and out, but still stiffer than normal. After an easy restart of the engine, I was then unable to reduce RPM to below 2250, with choke on or off. Normally it idles at around 1800 when the oil temperature has warmed up a bit. Shut down and removed the cowling. the choke cables appeared free of obstruction and cycled freely.
I flew, hoping this would clear in flight at full power and had the same thing in flight, unable to reduce power to idle on final approach. I put choke on in flight and as per normal it did not influence engine speed. I ran the engine through all regimes with no problems. I had flown the day before and all else was normal.
the engine has no history of problems and has a total time of 230 hours.
But overnight, this?
Be grateful for any suggestions.
Mike.
Puzzling one this :dry: Today when starting my engine (912ULS 100HP), I noticed that the choke knob was very hard to pull out, as if something was jamming the cable.
I pulled harder, and it did come out but was very stiff. I cycled the choke a few times, and it became easier to move in and out, but still stiffer than normal. After an easy restart of the engine, I was then unable to reduce RPM to below 2250, with choke on or off. Normally it idles at around 1800 when the oil temperature has warmed up a bit. Shut down and removed the cowling. the choke cables appeared free of obstruction and cycled freely.
I flew, hoping this would clear in flight at full power and had the same thing in flight, unable to reduce power to idle on final approach. I put choke on in flight and as per normal it did not influence engine speed. I ran the engine through all regimes with no problems. I had flown the day before and all else was normal.
the engine has no history of problems and has a total time of 230 hours.
But overnight, this?
Be grateful for any suggestions.
Mike.
