I am operating a 182 with an O470 and the CSU is not working correctly. What happens is the engine over speeds when it is throttled up to take off power before the governor kicks in, even with the throttle advanced very slowly. In addition to this, the prop sometimes refuses to cycle on the ground and if it does at least 2200 RPM is required, often more. Sometimes it all works well after a 2200 RPM cycle, ie back at 1700 RPM it functions as per the book, sometimes it doesn't.

The CSU unit was taken off and sent away for overhaul, found to be very worn and a brand new unit was fitted.
Another prop was tried.

Sadly the problem remains. Any suggestions here, Anyone familiar with the internal workings inside the engine? Engine oil pressure is fine at all temps.

Did you check your cable? Make sure its not sliding in a clamp somewhere. Cables can cause all kinds of issues.

Thanks for then reply A1, the cable was checked and all ok. Finally after much head scratching the problem was discovered and may be of interest to others with the O-470.

Inside the crankshaft behind the prop is a small plug with a tapered head that prevents oil from the prop CSU going the wrong way down the crank. In a million to one chance, this was loose. It was coming forward then needing a blast of high pressure oil from the CSU to re-seat it back where it belongs. Hence the prop being slow to cycle, initially intermittently, and then all the time. You can buy a few thou oversize plug which my engineer did. With the old one extracted (easy) this can be driven into place with a hammer and drift (rather hard and a bit scary).

Another interesting bit was that someone had tried to fix the problem in the past by increasing the oil pressure up to near the redline. This was also rectified by removing the washers they placed behind the relief valve spring.

Happy 182 now