Prop Governor Failure Mode

[carqwik]

I have a feeling that the prop governor is going bad on my bird. Curious as to whether other Bravo owners have experienced this...and what were the indications that it was starting to go south. And if so, what did you do to correct it? Mine has 1,000 hours and has never been overhauled or repaired...

[jetdriven]

What is it doing?

One failure mode I have heard of is wandering RPM and not staying on speed. . You might try the cheap fix first, cleaning the sludge from the inside of the crank nose. It can actually build up so thick it block oil to the prop hub. Pull the prop, look inside the end of the crank.

When we OH'd the engine we sent the governor off to Quality Aircraft Accessories. I spoke to the guy actually overhauling the governor about what I wanted and they were right on it. They exchanged mine for a different model number in 3 days. I used to have their dual magneto as well. Great shop. Talk to them about your symptoms as well.

[carqwik]

It wanders...if I set 2400 for cruise climb, it will wander +/-70 rpm and then will settle down on some number...readjust and it seems to settle down a bit. At the end of the climb as the plane transitions to level flight, the rpm's increase to 2500 or so....so I have to reset it again. Interesting comment on the cheap fix...I have heard of this although the oil stays very fresh in the plane and the engine/crank got worked on three years ago for the crank AD.

[Seth]

Yes - that unfortunately sounds like a prop governor failing. I didn't notice an issue with mine on my former M20F until I got a digital Tach. In climbs and decnets it started to increase or decrease (decrease on climb, increase on decent) by about 30 to 50 RPM. It technically was still in spec, but showed that an issue was brewing. It is actually amazing how far out of spec it has to be until replacement is requried.

Question, and not to start a debate, what type of oil do you use?

-Seth

[fantom]

Question, and not to start a debate, what type of oil do you use?

-Seth

I know what you're getting at Seth, but please start using oxygen when in the flight levels

[jetdriven]

It wanders...if I set 2400 for cruise climb, it will wander +/-70 rpm and then will settle down on some number...readjust and it seems to settle down a bit. At the end of the climb as the plane transitions to level flight, the rpm's increase to 2500 or so....so I have to reset it again. Interesting comment on the cheap fix...I have heard of this although the oil stays very fresh in the plane and the engine/crank got worked on three years ago for the crank AD.

one thing you might also check is for slop in the prop gov linkage. if there is play in that, you can set the RPM and it will wander as the slop in the linkage is taken up.

[Seth]

I know what you're getting at Seth, but please start using oxygen when in the flight levels

That's pretty funny - really not trying a debate - just hearing things around the hanger and from prop shops about certain oils "gunking up" prop hubs and governors more than others and without starting a debate, just wanted to know what he uses in that engine. I know what I used to use in my former aircraft and what I use now, what I'll have to use shortly, then what I use now, and then what I plan to use once the new cylinders are broken in (confusing).

But again, love the image.

-Seth

[carqwik]

Use Aeroshell 15W-50...since 2001 when I acquired the plane. The linkage from the cable to the governor was checked....it's tight as a drum. (Actually I did have that problem once before where the nut holding the cable to the "Z" link (that's what I call it) was loose and hanging on by safety wire only!) As far as the oil gumming up....I kind of doubt it but will check.

[jetdriven]

OK, 15W50 is half synthetic. And synthetic oil cannot hold lead in suspension. ROP operation puts more lead, carbon, and unburnt fuel into the oil as well. So there is a good possibility that you have a sludged up governor or crank bore. It centrifuges the lead bromide right out of the oil and sludges up the crank nose.

[carusoam]

It is possible to flush the system at oil change...

The method that the system uses is an old style mechanical mechanism, so that digital rpm gauges exceed the accuracy of the controlling device.

Best regards,

-a-

[N601RX]

governor, plugged governor gasket/screen, worn front crank bearing,oil temp to hot.

[jetdriven]

flushi

It is possible to flush the system at oil change...

The method that the system uses is an old style mechanical mechanism, so that digital rpm gauges exceed the accuracy of the controlling device.

Best regards,

-a-

flushing wont clean this out.

does anuyone else have this issue where photo uploads fail and "new content" comes back blank? Craig?

[carusoam]

Byron,

You're leaving me hanging....

That's a photo with an ugly glob of something in it.

-a-

[carqwik]

The shop tested the governor, found that it was slightly erratic, and went ahead and replaced certain parts and complied with a S/B which required some machining of an internal groove of some kind. (Not sure this is exactly correct as I couldn't find the SB.)

Well whatever they did, it now works just fine...@ $1AMU between inspection, parts, and labor....ugh!