M20F Possible Corrosion?

[CapPJ]

Hi All,

I'm looking to make an offer on a 1974 M20F. I was very excited to see the airplane in person last week but I noticed a few areas that caught my attention as possible corrosion concerns. The plane was painted in 2010, so exterior wise it is in good shape and the only thing I noticed was the flywheel teeth seemed rusted (behind the spinner), per below. Not sure if this is common as the plane has been tied down outside during this rainy season. In the interior I also noticed that the prop, mixture, cowl flaps and heat/vent levers appear to have rust spots, circled in green. I'm not sure if this is common for a Mooney of this age and if anyone has experience with dealing with this issue. If anyone has changed out these parts (also would like to change the cracked plastic on the levers), are we talking hundreds or thousands of dollars? I did notice that when closing and latching the door, there was a gap on the top rear of the door, so it didn't seal correctly. Maybe this caused moisture in the cockpit leading to corrosion? The broker mentioned I just need to fix the latch and install new weather stripping. I will definitely have a pre-purchase inspection done to understand if corrosion is a big factor here, but just wanted to get some insights from Mooney owners that may have dealt with this on their aircraft. Also, are these issues normally caught/inspected during an annual or is it beyond the items checked for? Really appreciate the feedback. Thanks!

 

[carusoam]

Start getting a feel for airworthy vs non-airworthy issues…

Even non-AW corrosion on control parts can be cleaned up…

the gear toothed starter ring is often coated from the factory… the light oxidation on the surface isn’t the kind that makes it fall apart…

Buying a new gear isn’t all that expensive… getting it installed will be a bigger surprise… see if it has all of its teeth… my M20C was missing one.  It is held in place using friction heat the ring to have it expand, keep the engine cool with ice, they come apart… prop has to be removed and replaced…

 

If you have two identical planes side by side… select the one with the fewer issues…

Corrosion and seriousness…

1) Inside the engine… huge AW issue when the cam lobes get ground off…

2) inside the steel tubing… huge AW issue when the tubes rot…

3) deep into the alloy structures… huge AW issue when deep into structural materials….

4) Surface corrosion is much easier to fix…. Intergranular corrosion is more serious…

5) Plastic panels for the interior… some are available new… some get rehabbed… plenty of reading around here for that…

Most Mooneys don’t suffer from these issues while actively cared for…

Open eyes, and annual inspections, are great tools to avoid this…

A PPI is the best insurance available when buying a plane… imperfect. But, best available…

My M20C lived outside for decades… a cover is a nice way to keep the excess heat and moisture away from important things… 

Plane parts are expensive… similar to car parts and boat parts…

 

PP thoughts only, not a mechanic…

Best regards,

-a-

[Ragsf15e]

1 hour ago, CapPJ said:

Hi All,

I'm looking to make an offer on a 1974 M20F. I was very excited to see the airplane in person last week but I noticed a few areas that caught my attention as possible corrosion concerns. The plane was painted in 2010, so exterior wise it is in good shape and the only thing I noticed was the flywheel teeth seemed rusted (behind the spinner), per below. Not sure if this is common as the plane has been tied down outside during this rainy season. In the interior I also noticed that the prop, mixture, cowl flaps and heat/vent levers appear to have rust spots, circled in green. I'm not sure if this is common for a Mooney of this age and if anyone has experience with dealing with this issue. If anyone has changed out these parts (also would like to change the cracked plastic on the levers), are we talking hundreds or thousands of dollars? I did notice that when closing and latching the door, there was a gap on the top rear of the door, so it didn't seal correctly. Maybe this caused moisture in the cockpit leading to corrosion? The broker mentioned I just need to fix the latch and install new weather stripping. I will definitely have a pre-purchase inspection done to understand if corrosion is a big factor here, but just wanted to get some insights from Mooney owners that may have dealt with this on their aircraft. Also, are these issues normally caught/inspected during an annual or is it beyond the items checked for? Really appreciate the feedback. Thanks!

 

You should get someone knowledgeable to open up the inspection plates under the wing and take out the interior carpets and seats for a prebuy.  You really need a good inspection of the spar.  What you’ve identified isn’t an issue by itself but it could indicate that there are other issues which could be a problem.

[ArtVandelay]

The cylinder looks new, what’s the history of the engine?

Pull the battery access panel and check out the condition of fuselage, control rods, etc.

If your back is in good shape, check underneath the panel.

What’s the condition of the yoke shafts?

Drain a sample from both fuel tanks, is fuel clean with no water?

[RoundTwo]

You said the plane was kept outside and your pictures confirm that. A warm, humid cockpit will produce a lot of lightly rusted screw heads on the panel. I’m assuming the plane has lived a humid life. In 49 years, that’s not hard to bellieve.

[Pinecone]

Where is the airplane?

[MikeOH]

Hmmm, this one looks to be a bit 'ratty' around the edges which leads me to worry about the 'guts'. Sounds like it's been sitting outside with a leaking door seal for how long?  How many hours has it flown in the last few months, and the last year?  If that's a 'zero' and 'under 10' I'd be even more inclined to continue your search.

[Fly Boomer]

13 hours ago, CapPJ said:

I was very excited to see the airplane in person last week but I noticed a few areas that caught my attention as possible corrosion concerns.

Einstein said "Whoever is careless with the truth in small matters cannot be trusted with important matters".  I would alter his idea to say "If the visible condition is questionable, the not-visible is likely to be questionable as well".

[CapPJ]

Thanks everyone for all the inputs! Yes I will definitely have a PPI if I continue with the buying process. The plane has not been flown in the last 3 months from what I can tell. The annual was done in Jan and there's only 1 hr added to tach time since. It has lived in Southern CA from what I can tell and now tied down at Cable Airport in Upland, CA. I know the plane will need some TLC and upgrades and right now I'm debating whether to go with this or another plane that's 30k more that seems to be in better condition. I'm prepared to spend the 20-30k additional for anything that needs attention as well as upgrades.

[Jsno]

Be sure to pulll the side panels and check the tubing for corrosion.  Also be sure to pull  the seats and carpets and check the spar for corrosion.  Any metal in the filter will probably be a bad cam.

[MikeOH]

3 hours ago, CapPJ said:

Thanks everyone for all the inputs! Yes I will definitely have a PPI if I continue with the buying process. The plane has not been flown in the last 3 months from what I can tell. The annual was done in Jan and there's only 1 hr added to tach time since. It has lived in Southern CA from what I can tell and now tied down at Cable Airport in Upland, CA. I know the plane will need some TLC and upgrades and right now I'm debating whether to go with this or another plane that's 30k more that seems to be in better condition. I'm prepared to spend the 20-30k additional for anything that needs attention as well as upgrades.

PM me if you want me to go lay eyes on the plane.  I'm close to CCB and could swing by after work.

[thinwing]

what that starter gear ring is telling you...is that this plane has not flown or even started in quite some time...that appears to be very thick rust