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Prop Surging

I’m experiencing prop surging on takeoff and when adjusting power at altitude. Generally it seems like it’s hunting to stabilize when I move the prop lever. Sometimes it prevents an over speed, sometimes it has a momentary over speed. A few times it oversped by 100-200 RPM and then sank below max by about the same amount before oscillating back to the setting I wanted. At static runup we managed to get it set just below 2700 with no overspeed. Is the fix simply adjusting the max RPM stop? Or do I need to go back and adjust the fine pitch stop again? Or is surging another issue entirely?

This is a newly installed Hartzell HC-C2YR-1BFP with a Hartzell S-1-10 governor from Vans.
 
I would speculate that something is not right with the governor. I have an S series governor on my 10 and it is rock solid with absolutely no signs of surging or hunting, even while adjusting new speeds.

Did you by chance remove the outer cover (the one with the adjusting arm in it) when you re-clocked the lever? If so, you may have messed up the re-installation procedure and let the shim under the internal speeder spring fall out. There is also a special procedure for clocking the outer spring. If not followed, either of those things could cause your symptoms.

Larry
 
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Mine surges on take off momentarily then “finds” correct RPM. Mx shop said normal

The initial runup to full RPM on T/O will routinely do this. The governor can't react quick enough to such a large and rapid RPM change, so the prop will run up to whatever RPM is supported by the fine pitch stop and within a few seconds, the gov catches up and regulates. Any hunting after the first few seconds of T/O was what I was referring to.

Larry
 
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