New to me '65 M20C - Annoying radio mounting, water in my fuel, and other questions

[jeremyc209]

Hey all, I posted in the classifieds about my m20c getting a fresh annual and needing the fuel drain valve, thanks for the suggestion on putting a standard drain on there, Maxwell got me the part numbers and got it straightened out.

I took delivery a couple weeks ago (photo from a friend that gave me a ride to pick it up) and it's been great so far even though I've only flown a couple hours. I do have a few things that are top of the list to get taken care of. I'm sure I'll have more questions, I'll just keep them in one thread here to keep the clutter down.

1. The center stack is mounted funky, and I've not seen this in a Mooney before. I have an appointment with the avionics guys in a week (they are also diagnosing a weak signal to both nav radios) and wanted some opinions. They thought maybe something was in the way behind the radios but I crawled under there today and it looks like there's plenty of space behind them. The radios are supported by a strap behind there, I don't see any reason why the whole stack can't be flushed up with the panel. The bottom radio in particular is super irritating as it interferes with throttle control.

Will the avionics shop be able to remount the whole stack so it's flush with the panel?

Related question: Both nav radios have almost no VOR range, maybe a mile or three. Sounds like the antenna cable/splitter. Anything common to this model they should look at first?

2. We got some rain while I was out for a week on vacation and got my first water in the fuel samples. 3 sample flasks worth! I'd never seen water in a fuel sample previous to this. Upon closer inspection, my nice new cap o-rings aren't going to do much. The left tank isn't too bad and will probably clean up, but I've attached pics of the right tank fuel cap assembly (part number 610036-503).

Is it possible to repair these and refinish the surface? Should I start searching for a good condition replacement?

[47U]

40 minutes ago, jeremyc209 said:

Will the avionics shop be able to remount the whole stack so it's flush with the panel?

Related question: Both nav radios have almost no VOR range, maybe a mile or three. Sounds like the antenna cable/splitter. Anything common to this model they should look at first?

As to the fuel caps, I suspect you might need to replace the filler necks.  They look pretty bad.  Not sure if they’ll clean up.  Caveat, I have different fuel caps in my ‘63 C so no real experience.

The nav antenna was replaced in my C by the previous owner in 2007 or 2008, same issue as you, weak nav signal.  It might be time.  Obviously the coax and connectors require inspection… or replacement.  

There’s a couple structural tubes behind the panel restricting the center radio stack at the top.  Nothing with any depth fits.  It looks like the previous owner tried to shoe horn in more radios that will fit by mounting them at an angle to clear the tubes.  Some different radios would be the solution.  Trig makes a nav/comm that’s only 1.3” tall, TX56A.  Or Garmin… I think has a new replacement for the SL30.  

Calaveras?  Not too far away.  Enjoy your new to you Mooney!

 

[Utah20Gflyer]

The radios could definitely be remounted in a more conventional manner.  I don’t suspect that would be terribly expensive as it doesn’t require any rewiring.  The trays just need to be remounted and supported correctly. 
 

The radios are TKMs, they don’t have a particularly good rep for longevity or repairability.  I had one in my plane that was bad when I bought it.  The easiest way to troubleshoot is to swap a good radio out for one that isn’t working.  If the symptoms go away it was the radio.  If they don’t it’s some other issue.  Unfortunately for you sounds like both radios are having issues.   You could check all the connections and see if something looks wrong.  Could be something came loose.
 

 You probably also have a King KI214,  they also have lots of problems.   King Kx170/175s and the TKM replacements didn’t come with internal glideslope receivers so you have to pick up GS with another device.  The 214 was a popular pairing because it came with an internal glideslope receiver.  They generally aren’t repairable.  
 

The TKMs are a slide in replacement for a King KX170 or 175 radio.  I bought a KX 175 to verify my radio was bad and then also to use until I could afford a swap out for a Garmin 255 nav/com.  Still have it if you want a cheap replacement.  
 

That fuel filler doesn’t look refinishable to me.  It will probably need to be replaced.  It just looks too far gone to ever seal properly.  You could always take some very fine sand paper or steel wool to it but unless that is a build up of some sort I don’t think you’ll be able to get rid of that pitting.  
 

If you have to store your plane outside wing covers are great insurance against water getting into your fuel tanks.  
 

Congratulations on the new acquisition!  

[Bob E]

47 U just said pretty much the same thing as this post, but a couple of minutes earlier!  I'll post this anyway.

-------------------------

Ok, where to start?   First off, it's a nice Mooney!  The irritating stuff can all be fixed.

• You can get replacement fuel-filler flanges. You're right, that's where the water is coming in, and new o-rings won't help.  Replace the entire racetrack-shaped piece on both sides. You do it once every 30 years. I was able to find new ones 15 years ago and the filler flanges still look new.  (I've owned my '65 C for 40 years now).
• Given the deterioration of the fuel-filler flanges, it's safe to say that this aircraft wasn't hangared for years (similar to mine until 5 years ago). That means the weak VOR signals are probably the antenna connector, either at the radio itself (likely) or at the antenna, or both.
• That's a really stupid avionics stack install. Whoever did it should have known better.  The fuselage steel frame has a y-junction that takes up some space at the top of the radio stack (photos), which means you can't install something that has much depth at the top of the stack. It should be a fairly simple matter to reconfigure the install to take into account the y-junction.  Just put something that doesn't have much depth at the top.

[jeremyc209]

Yep, I'm at CPU. Trained and got my cert here in Oct. I drove to LHM to take the written before I started training. 

The filler necks can be replaced without replacing that whole panel? 

And that makes sense about behind the radios, but weird how everything is mounted like that including the old AP and audio panel. These are replacements for KX-170s too, which I think came in some of these back in the day. I guess we'll see when they pull them to check the antenna and cables.

 

[jeremyc209]

12 minutes ago, Utah20Gflyer said:

The radios are TKMs, they don’t have a particularly good rep for longevity or repairability.  I had one in my plane that was bad when I bought it.  The easiest way to troubleshoot is to swap a good radio out for one that isn’t working.  If the symptoms go away it was the radio.  If they don’t it’s some other issue.  Unfortunately for you sounds like both radios are having issues.   You could check all the connections and see if something looks wrong.  Could be something came loose.
 

 You probably also have a King KI214,  they also have lots of problems.   King Kx170/175s and the TKM replacements didn’t come with internal glideslope receivers so you have to pick up GS with another device.  The 214 was a popular pairing because it came with an internal glideslope receiver.  They generally aren’t repairable.  
 

The TKMs are a slide in replacement for a King KX170 or 175 radio.  I bought a KX 175 to verify my radio was bad and then also to use until I could afford a swap out for a Garmin 255 nav/com.  Still have it if you want a cheap replacement.  
 

Congratulations on the new acquisition!  

Thanks! I suspected the antenna or cable because both radios and both indicators function almost identically. I can tune the same freq, get nothing, and within a few miles of the station both will come alive around the same time and indicate more or less the same. 

I have 209 and 208 indicators, and the glideslope box in the tail is a KN-75 if that makes any difference. I haven't tested that at all. 

The DME works fine, so I'm hoping I can get the nav radios functioning for a basic IFR setup to practice with. 

[jeremyc209]

12 minutes ago, Bob E said:

• That's a really stupid avionics stack install. Whoever did it should have known better.  The fuselage steel frame has a y-junction that takes up some space at the top of the radio stack (photos), which means you can't install something that has much depth at the top of the stack. It should be a fairly simple matter to reconfigure the install to take into account the y-junction.  Just put something that doesn't have much depth at the top.

Yeah these are bottom of the stack radios and they have some play and plenty of space that I can see from the bottom. Hopefully they can sort it. 

The plane was kept in a hangar by the previous owner for almost 30 years, not sure why he let the fuel filler necks go so long without addressing them though.

[Utah20Gflyer]

Just now, jeremyc209 said:

Thanks! I suspected the antenna or cable because both radios and both indicators function almost identically. I can tune the same freq, get nothing, and within a few miles of the station both will come alive around the same time and indicate more or less the same. 

I have 209 and 208 indicators, and the glideslope box in the tail is a KN-75 if that makes any difference. I haven't tested that at all. 

The DME works fine, so I'm hoping I can get the nav radios functioning for a basic IFR setup to practice with. 

I think the KN 75 is a much better setup than the KI 214 so I think you dodged a bullet there. 
 

You could be right about it being the splitter.  Hopefully it will be that instead of the TKMs.  
 

My audio panel is a little more than an inch down from the top to avoid those steel tubes so 47U  could be right about someone angling everything on purpose to wedge it all in.  You might consider getting rid of the ADF and moving the autopilot to that position so you can move the audio panel down.  There are so few NDBs now a days I’m not sure ADFs are worth keeping anymore.   

[jeremyc209]

Found the stainless fuel filler necks on Lasar, I think, $740 each  and out of stock. Will make some calls. 

Anyone have a good preflown set? Is the stainless replacement pretty much the only route? 

[Sabremech]

4 hours ago, jeremyc209 said:

Found the stainless fuel filler necks on Lasar, I think, $740 each  and out of stock. Will make some calls. 

Anyone have a good preflown set? Is the stainless replacement pretty much the only route? 

It’s not the only route. I installed new fuel caps and flanges in the 66C I previously owned. My 337 with parts listed is on MS but I’ll look for it and post it here for your info in a day or two, 

David

[Hank]

@Alan Fox has some preflown parts, and he's also scrapped out a Mooney or two. He may have some filler necks, even radios if they're the problem. 

Welcome to the club. Hope you enjoy your C half as much as I do mine!

[Aaviationist]

I think you had better have someone really good look over that airplane before you continue. I’d bet that airplane spent a lot of time sitting outside unused. 
 

id bet you’re going to find a bigger list. 
 

I really hope this was sub 50k for the journey you’re about to be on. 
 

what was the tail number before it was changed?

Edited 7 hours ago by Aaviationist

[jeremyc209]

2 hours ago, Aaviationist said:

I think you had better have someone really good look over that airplane before you continue. I’d bet that airplane spent a lot of time sitting outside unused. 
 

id bet you’re going to find a bigger list. 
 

I really hope this was sub 50k for the journey you’re about to be on. 
 

what was the tail number before it was changed?

What information are you making these assumptions on? 

I had an extensive prebuy/fresh annual performed and it was not sitting outside. It's a local plane and had spent the last ~30 years stored in a hangar, well cared for, and flown regularly. I'm assuming the old timer I bought it from didn't spend much time out in the rain.

We stripped the interior and inspected every inch of the airframe. We missed the fuel filler neck on one side, the other side is fine for now.

Any 60 year old aircraft will have a few squawks to deal with. Not sure what you're on about.

 

[MikeOH]

57 minutes ago, jeremyc209 said:

What information are you making these assumptions on? 

I had an extensive prebuy/fresh annual performed and it was not sitting outside. It's a local plane and had spent the last ~30 years stored in a hangar, well cared for, and flown regularly. I'm assuming the old timer I bought it from didn't spend much time out in the rain.

We stripped the interior and inspected every inch of the airframe. We missed the fuel filler neck on one side, the other side is fine for now.

Any 60 year old aircraft will have a few squawks to deal with. Not sure what you're on about.

 

Not to worry; Aaviationist is just the local curmudgeon.  Don't pay him any attention

[Aaviationist]

1 hour ago, jeremyc209 said:

What information are you making these assumptions on? 

I had an extensive prebuy/fresh annual performed and it was not sitting outside. It's a local plane and had spent the last ~30 years stored in a hangar, well cared for, and flown regularly. I'm assuming the old timer I bought it from didn't spend much time out in the rain.

We stripped the interior and inspected every inch of the airframe. We missed the fuel filler neck on one side, the other side is fine for now.

Any 60 year old aircraft will have a few squawks to deal with. Not sure what you're on about.

 

Based on the condition of those filler necks I suspect this airplane spent a considerable amount of time outside. 
 

if you had a good prebuy, I would think fuel caps and filler necks would have been noticed as that’s a pretty well known issue. 
 

im suggesting you go through it carefully as this likely isn’t the only thing you’re going to find. 
 

a good prebuy buy and an annual are NOT the same. 

[Pinecone]

Either outside or a hangar with some leaks.

One temporary fix would be covers to go over the caps to the keep the water out.

https://www.aircraftspruce.com/catalog/pspages/jpt_13-21885.php

 

[jeremyc209]

What's this under the panel? Looks like a light of some sort, footwell lighting? One wire pulled from the crimp connectors. Copilot side