NicoN

Thank you for the picture. As far as I understand, the trim switch has 2 functions: 1,. It activates the clutch (middle switch) 2. It works as a voltage reversing switch. Normally (doing nothing), both output lines are grounded. Operating the lever in one direction or the other just switches the posles. It is a typical schematic called "H" to reverse DC motors My problem is not the switch, it is that all cables are torn off. So, I have 6 cables and not an excat idea what they do. I have ... 2 cables (red/white and purple white) connected to 12V via Elev trim C/B 1 cable (yellow white) which seems to be connected to aircraft GND 1 cable (blue/white) which activates the clutch if you connect it to one of the 12 V cables 1 cable (black/white) going to the Trim Intterupt button with a little blue wire coming back from there. It has 12 V, but is not strong enough to power the clutch 2 cables which I was thinking is the DC motor itself. But the motor does not activate, it is simply silent. And also, I do not find a resistance between the 2 cables (unlimited) For a DC motor I would expect a low resistance between them Any idea of how the switch (and especially the cbles work ?

it is exactly this siwtch. The switch is perfect, I think. But cables are torn off, so I need some help what the switch does and which cables are there. There is on cable coming from the TRIM INterrupt button which has 12 V on it The button has no splited button. It contains 3 little switches. 2 for up/down and 1 for the clutch

Actually our M20k has no ALT-hold originally. We have an S-TEC 60 PSS, but this guy does not affect Elevator-Trim This switch has the up/down function and by pushing it activates a clutch. So, normally you can hear the trim motor running by activating the up or down function, but the trim wheel does not move at all. This happens only if you push it down also.

We actually have trouble with the ectrical trim switch in our M20K /S/N 25-385). For a qhile we have seen the Fuse/switch for the electrical trim trapping some times. Today, I opened the yoke to change the MIC-button and almost all of the cables were torn off ( or I gave some wires the rest:-( ) So, I was looking on my printout of the electrical scheme and - I did not find this switch ( shame on me). On top comes, that my PDF of the maintencance manual is corrupt and no more readable So, please: 1. Is the PDF of Maintenance manual available somewhere 2. Has someone an idea of where the trim switch is located on the electrical scheme and how that switch works ? I think , it is not part of the A/P (which is a Century 21), as this A/P has no ALT-hold function. Thank you a lot

@PT20J: Sounds doable. But still heavy, i think. I guess, I still need a second person

Just joking :-) But, it is too heavy for me

First, the maintenance guy say, it helps and accelerates the oil-drain and should even reduce the mess when removing the oil filter. Second, I think it could help to get better access to the bottom of the fuselage. At the moment I am using one of these roling beds and still have not much clearance to remove the belly covers

My question may sound stupid: Our maintenance guy somehow lifted the front gear on a low stool to make oilchange and all work easier. I did not remember how he did this. I only know, he did this in his own without help these days I wanted to do the same and failed . It was simply too heavy to lift at the prop ( or I was to shy) and I decided it is not a good idea to push on the tail. Any ideas how to get this done without being in a wrestler-like shape? EDIT: It's an M20K with the large. heavy 6-cylinder big-block-engine

Our M20K has a Century 21 A/P - so no auto-trim. But we have electrical trim - as mentioned with the combined switch on the yoke, a rocker switch and a separate c/B

Yesterday I found the Elevator Trim ON/OFF-switch in OFF-position for the second time. It was always discovered after take-off (shame on me), because the electrical trim was not working After switching to ON anything was fine. But, I am thinking why it was found in OFF-position. Normally, this switch is never used and always in ON AFAIK, this switch is also a C/B, so, it might be trapped rather than swapped to OFF by a human being. AFAIK, the electrical elevator trim has lots of items to switch it off: - the TRIM interrupt-button on the yoke - a C/B in the panel as part of the rocker switch assembly directly next to the yoke column - why this in addition to the rocker-switch? - a separate rocker switch (with C/B-function?) to switch electrical trim on or off My first idea is/was: I was flying with to people only in the front seats. So, I supposedly used maximum nose-up trim for the landing. Maybe, the trim motor ran into mechanical stop and caused the switch-type C/B to trap ? Aren't there limit switches on the trim motor gear ? I don't have a maintenance manual with me right now, so just an idea. It is a Mooney M20K-231 from 1980

@kortopates: Thank you for your information. Extremely interesting. We have a M20K-231 equipped with an EDM830. The recommended procedure for lean finding needs to pre-lean the engine to a certain ROP position, then wait and after minutes do the lean-finding. I tried this procedure pretty often. but always start the leaning pretty soon. as the temperatures are quickly rising! So, now I lean more or less down to 11.5gph, wait only few seconds and then to the lean find procedure. The EDM830 never failed to detect the LOP point. I always further lean to stay between 30 to 70° LOP and end up at 8,2 to 9.5 gph and temperatures max of 365 CHT for #2 and TIT ~1520 (TSIO-360GB). But, during the Lean-find, the Power decreases from 67% down to ~58%. Is it legal to advance the throttle then to come back near 65%? Doing this, I see sometimes the EGTs even more decreasing, then increasing again. I never ever go higher than 65% LOP

thank you for all of your answers. Indeed, I see no problem by pulling the Mooney forward. Pushing backward or manouvering the aircraft into the hangar seems to be problematic: You always have to lift up the SchleppMaxxe, move it to the side ( of course maximum possible angle). I will look for a another model

Since many years we are using a so called "SchleppMaxxe" electrical towing device to move our M20K. It grabs into that pipe in the front gear where also the the normal towing bar is fixed. My concern is the limited turn angle of the front gear. To move our aircraft we have to lift up the "SchleppMaxxe" and move it from one side to the other Recently I read about the danger of damaging something on the front gear. It is the model TF1 from https://towflexx.de/flugzeugschlepper/, but there should lots of other models from different brands around What is the best practice in moving the aircraft?

What's wrong? In my dreams, after such an avionics upgrade there is only a thin cable left for the CAN-Bus hopping from one device to the next and maybe a few thin, short cables for addtional RS232 or ARINC for special purposes. And 2 little hoses for static and pitot. That's it. Lots of air and space behind the panel. But yours looks different. Hope, this picture was taken BEFORE the big pull of cable removing

@Emmet: Your gasket may be failing. My leakage was at the bottom, below the fuel hose and even under that small flat profile. You also have fuel tracks in the back corner where the main spar is.

We have Shaw 431 fuel caps. And they are painted. Over the years and especially as my co-owner were using pliers to open and close them, they now look awful. Is it possible to strip off the paint and polish them? Just an idea. I like those polished fuel caps

Update: in my original posting I talked about a rheostat in combination with a big resistor with a cooler. Also the schematic seemed to me that the regulation is simply converting power to heat. But I was wrong! Even in my schematic there are 2 transistors for panel lighting and instrument lighting on the far right end of the schematic. And these are controlled by rheostat and resistor. only the compass lighting seems to be independant ... shame on me Q1: Why the hell is there a C/B for panel lighting and another fuse near the transistor ? To be honest: I have never seen the transistors, but only 4 grey plastic caps where fuses are under. This is located under the RH panel. Q2: i am not an electrical engineer, but is it possible to replace the combination of rheostat and resistor with a PWM dimmer? This could mean, the PWM dimmer is providing switched power to the transistor and this one siwtches on and off my glare shield lamps (or LEDs) Thank you!

We had exactly these problems: - The fuel cap was hard to handle. Only possible with pliers ( now they look accrodingly :-( ). You can adjust the fuel caps with the castle nut. But it is also a good idea to change the gaskets. We have the "-431" caps. You are in EU? I can send you the source for the gaskets. We also had that fuel smell. After removing the interior panel there were lots of blue tracks from AVGAS. The isolation foam was soaked with AVGAS and stinking. The leak came not from the fuel sender but from the corner wing/first rib. Use kitchen paper towels to find out the location for the leak. But it may be misleading as the AVGAS seems to go everywhere.

My question may sound funny: In 2017 (before i entered the group of owners) our tanks were re-sealed. According to the bill RH AND LH. In summer 2019 I noticed fuel smell in cabin and in winter, I removed the interior panel and found blue AVGAS in the lower edge of the first wing rib. (LH) Also, in summer 2019 I have seen blue "tracks" on one of the tank access panels on the upper side of the wing (also LH) but only when the tank was filled to the max. It seems, I was the first person to push our Mooney to the limits and filling the tanks to the MAX. Okay, recently the LH tank was re-sealed by the same maintenance which did the first procedure. Of course, they presented us a high bill for that - and we do not want to pay for it. The first attempt was, they told us, the LH tank never was re-sealed. Now the question is - which life-time can I expect from a tank sealing procedure? The maintenance guy says, that it is completely normal for a tank leaking again even after roughly 2 1/2 years. Hot temperatures can cause this (our Mooney lives in a hangar for 98% of the year!), cold temperatures can cause this, every landing(!) can cause this. Hey guys: We are living in mid-Europe, it does not get excessively hot and not super-cold in winter!!! I think, I can expect several years of non-leaking at least, but not 2 or 3 years. What is your experience with re-sealed tanks ??

Did I read the Garmin compatibility list right: Our Century 21 is supported but not our S-TEC 60PSS which does altitude hold. Is there any solution to have Altitude pre-select. I know that there is a little even cheap box around which can simulate a ALT pre-select at least for Aspens.

Funny. I am absolutely sure I have seen only a rheostat and this resistor. And this is according to the schematic ... Definitely no electronics box ...

Today I was lying under the panel and was surprised to see a resistor in a kind of cooling metal housing next to the potentiometer for glare shield lighting. I was expecting some fancy electronics. According to the schematic this seems to be true. Is this really true that my light bulbs are controlled by a variable resistor ? What Äs the addditional resistor is for ?

When i first transitioned to my 231 I had lots of failed starts in the first time using the primer. The engine dired fine, ran 3-4 seconds and then started to die or died. Feeding it with the primer pump fro several seconds prevented that, but always gave me a roraing engine spooled up to 2000 or more RPM and forced me th pull back the throttle - and the engine sometimes died again. Anything changed by accepting a method from here: - Full rich - Throttle wide open - Then use the high boost pump for 6-8 seconds (8 in winter) - wait for ~ 10s - close throttle to position for ~1200RPM - crank the engine I never again have seen the engine dying. It runs smooth from the first second with ~1200-1400 RPM. May be thuis can help you

Thank you. Removing the wire from the speaker is the last option. The new audio panel is also not an option at the moment. So, I can live with it.

in our 1980 M20K we have a constant noise on the cabin speaker. It is nothing new, it is it least since 3 years when I joined the group. it is not serious and alo not really disturbing, but it is noticeable, especially on ground with no headsets on. We have the venerable KMA 23 I think and the noise is always there - no matter if some or no audio source is activated for the speaker on the KMA. The audio quality on the speaker is poor, but not due to noise and communication via headsets is excellent and definitive not a problem. So, let me ask if this is a common or even "well-known" effect which can be eliminated? Thank you