My F1 EVO with a 540 while in a decent and throttle position unchanged has never held RPM and it will climb regardless of pitch control position. I did speak with Stockton propeller and bever received a clear answer as to what could be wrong. I purchased the plane right after the prop was returned and installed so I don't have history on it. I do know the governor was brand new. I am reading through the manual now and see If i can get any info before my mechanic takes a look. Going to have it balanced in a few weeks also
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PC 5000X Governor Question
- Thread starter Robb
- Start date
Is it possible your prop is hitting the coarse pitch stop?
I found that my RPM doesn't hold if I descend at lower RPM settings, so now descend at lower descent rates (2% glide slope) or ~ 500 FPM. Use to use the default 3% in the Garmin GTN and lower power settings (~20% engine power). I have the PC 5000X on my 390 and also on the 540 and the 540 seems more susceptible to lower power settings than the 390. Now use 2% and ~30% engine power and RPM seems to hold much better. Plus, my thoughts were descending a slightly higher power settings better for the engine but of course no documented data to go with this.
I think you are right. I flew today and after cooling off my cylinders I lowered the manifold pressure and it held RPM. Too much throttle and it runs away
I used to work there (39 years) and have built hundreds and hundreds of these governors, both experimental and certified. Depending on which "Base" unit your governor was made from, it may benefit from an "E" speeder spring. The tighter E spring allows more control/psi at lower rpm. If they used the base unit I think they did, you would most likely have a G spring. If it is under warranty send it back. Give them written direction "Loss of control at lower power settings, prop needs more pressure at lower rpms". If they balk at it, or say there is nothing wrong with it, let me know. I still know and talk to almost everyone that works there. Since this is experimental, I could always go there and swap the spring and run it on the test rig myself. To change the spring, the governor will need to be run on the test rig and be adjusted. The tighter E spring effects how/when the flyweights open. I can do it start to finish it in about 20-30 minutes. It takes longer to safety the screws on top than swap the spring and run it. I'll PM you my cell number.
Would this also be a solution to stop a condition where the rpm "surges" 10-30rpm when set 2600rpm or higher? The governor holds rock solid below 2600rpm. It held rock solid before overhaul, since overhaul it wanders a bit when above 2600rpm. I sent it back to the shop once already and they "increased the relief valve pressure".
