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28 minutes ago, Skates97 said:

If you want to make your fortune you better change the logo to Beech and market on their forums, we all know Mooney owners aren't going to make you rich! :lol:

Do Beech owners change their own plugs? :) 

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3 hours ago, takair said:

Just to rule the governor out, on the next run up, pull the prop knob and see if and when the RPM reduces more....in other words, when you are "on the governor".  At that RPM, it should be far from governing.  If the prop responds right away, something is going on and the governor is limiting you.  Don't see how this would explain the roughness, but as others have said, may be two problems and this test is free.

I did cycle the prop control, and even at max static of 2250-2300 it does reduce to 2000 or below.  I never left it pulled out all that long or paid attention to the exact "low end RPM" just that it would cycle.  Started engine fine, and let it set at 1000 RPM for a few minutes while watching oil and cyl temps. When in the green is when I first went to 1700 for L/R Mag check (all normal with about 75 RPM drop) and then up to 2000 RPM for prop cycle. Just assumed that governor should limit RPM to somewhere below 2000 ????

-mark

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Forgot to answer engineering question:  I have both ME and EE degrees and went back and got a Masters in an unrelated field at age 60.  Would have been a professional student back in the day, but got tired of being dirt poor.  I hail from Purdue.  Never took my PE exams but my son has his PE and he will own this contraption some day :). I've owned and operated a couple machine shop type manufacturing companies so I know all about fixing old worn out equipment and having scraped knuckles and grime under your nails.

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18 minutes ago, Mark942 said:

I did cycle the prop control, and even at max static of 2250-2300 it does reduce to 2000 or below.  I never left it pulled out all that long or paid attention to the exact "low end RPM" just that it would cycle.  Started engine fine, and let it set at 1000 RPM for a few minutes while watching oil and cyl temps. When in the green is when I first went to 1700 for L/R Mag check (all normal with about 75 RPM drop) and then up to 2000 RPM for prop cycle. Just assumed that governor should limit RPM to somewhere below 2000 ????

-mark

A proper A&P will be along shortly but I'd do the prop cycle again but a bit differently. First of all, set 1600 RPM. Then pull the blue knob just a 1/4" or so, then just a bit more. Going nice and slow, how far do you have to pull the blue knob out before the RPM's start to drop. That's what we want to know.

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44 minutes ago, Mark942 said:

I did cycle the prop control, and even at max static of 2250-2300 it does reduce to 2000 or below.  I never left it pulled out all that long or paid attention to the exact "low end RPM" just that it would cycle.  Started engine fine, and let it set at 1000 RPM for a few minutes while watching oil and cyl temps. When in the green is when I first went to 1700 for L/R Mag check (all normal with about 75 RPM drop) and then up to 2000 RPM for prop cycle. Just assumed that governor should limit RPM to somewhere below 2000 ????

-mark

Paul is correct.  We want to see if the governor is governing too early.  At static RPM it really shouldn’t be governing until 2700 and it should get there because the blade are at the low pitch stop.  Not sure why it would suddenly do that, but the governor has a lot going on and it may be telling you something.  Basically, in this case you don’t want it responding right when you pull the knob.  It would be rare for the prop to fail at high pitch, but there is a possibility that it’s not getting to flat pitch.  

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57 minutes ago, takair said:

Paul is correct.  We want to see if the governor is governing too early.  At static RPM it really shouldn’t be governing until 2700 and it should get there because the blade are at the low pitch stop.  Not sure why it would suddenly do that, but the governor has a lot going on and it may be telling you something.  Basically, in this case you don’t want it responding right when you pull the knob.  It would be rare for the prop to fail at high pitch, but there is a possibility that it’s not getting to flat pitch.  

Thanks guys for the input.  As soon as I can get the apron and taxiway clear of snow, I will pull the plane out and re run the governor test taking good notes.  I'll post my results as soon as I do.  Might be a few days as the weather here is pretty cold and been snowing almost every day.

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Mark,

Are you familiar with the gov operation?

two fly weights, a control valve, and a gear pump...

Fly weights have a tendency to wear and cause control issues...

The conic valve has a seal that can get dirty and or leak...

The gear pump is what supplies oil pressure to the blades... constant flow of oil goes to the valve...

The fly weights position the valve to send more or less oil to the prop...

The fly weights move with the engine rpm...

Unless you fly a Missile or Rocket...  a failure of the gov (low gov oil P) usually leads to it trying to go to max rpm...

The system seems to be behaving as if the control knob isn't going all the way in...

Or the internal conic oil valve is stuck delivering pressure to the prop...

Could be the fly weights that are stuck, holding the valve in the wrong position...

There are specs for wear on the internal parts of the gov.  

Is it time for a gov OH?  How many hours on the gov?  Good news, New govs may be lower cost than an OH...

PP Thinking out loud, not a mechanic...

Best regards,

-a-

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