Carburetor question

Jdm

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Jdm
I need a carburetor for the 172M. O320E2D. The P/N removed (10-5135) has been on since the engine was overhauled at Barrett MANY years ago. This P/N is still available today from Marvel Schebler. Prior to ordering it I decided to check to make sure it’s really the correct P/N for my engine. Lycoming says P/N 10-5217 is actually the correct carburetor. It’s also readily available from Marvel. The interesting thing is that 10-5135 appears to supersede to the new 10-5217, but they are both still being made and overhauled. And they are priced differently, with the 5217 being cheaper. Obviously something is different between the carburetors or they wouldn’t still make both at different prices. So which should we go with? I’m thinking the newer number. Anyone have experience with the two numbers and their compatibility?

Also noticed that Marvel offers this as an overhaul and a rebuild. The rebuild is more expensive. Has anyone compared the actual difference between the two levels of a carburetor repair? Is a rebuilt really that much better than a OH? Can’t imagine there being much difference.
 
Isn't there the option to have the original rebuilt?
 
I’m thinking this may need a little more research.

The holder of the Aircraft Type Certificate generally dictates appliances allowed

to be installed.

Hence; even though Lycoming says it’s ok, if Cessna ( Textron) does not agree

you may find yourself not conforming to the Type Certificate and hence

not Airworthy.

Piper specifically lists the required carburetor in the AIRCRAFT Specification

for the PA22 & PA 28.

Perhaps it may be related to the Aircraft Specification to Type Cert Data Sheet

change of format.

A critical part of an Annual is conformity to the Type Certificate.

Often the inspection reveals items like props and carbs that are eligible on

the engine but not on that aircraft.

Perhaps someone may chime in on this?

The difference between the 2 models may have to do with how rich the

mixture is in some portion of the operating range.
 
I’m thinking this may need a little more research.

The holder of the Aircraft Type Certificate generally dictates appliances allowed

to be installed.

That’s a good point, but couldn’t find anything in the aircraft parts manual.

Isn't there the option to have the original rebuilt?

Sure, but that doesn’t answer the question about correct application. An exchange is the same price as a having this one overhauled and eliminates the long wait.
 
Aircraft Type Certificate generally dictates appliances allowed to be installed.
FYI: a carburetor is not an "appliance" as it is part of the engine TCDS/specification. An appliance is any device or equipment used in the operation of an aircraft not associated with an airframe, engine, or propeller certification, i.e., TCDS. Examples would be instruments, radios, switches, circuit breakers, seatbelts, life vests, etc. While it can be confusing one reference to look at is the apppliance AD listing for more examples. So Cessna would have no say so as Lycoming is the controlling reference.
 
So which should we go with? I’m thinking the newer number. Anyone have experience with the two numbers and their compatibility?
Call Lycoming support and ask if there is documentation on the difference or simply ask the rep why the 2 options. When I have similar questions my 1st call is usually to the applicable tech support as a majority of the time they have the answer or can find the answer/reference I need.
 
Excellent clarification of the term “appliance”. I’ll try to remember that one!
We’re thinking alike in regards to calling Lycoming. I called their support line yesterday before posting this. They are the ones who initially gave me the new 10-5217 number. They seemed a bit confused about the old 10-5135 number and didn’t really have any additional information about it.

Update. I was wrong about it not being in the Cessna parts catalog. I found an old part number in the IPC this morning. Maybe I can cross it over.
 
Excellent clarification of the term “appliance”. I’ll try to remember that one!
Heres the official Part 1 definition:

Appliance means any instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including communications equipment, that is used or intended to be used in operating or controlling an aircraft in flight, is installed in or attached to the aircraft, and is not part of an airframe, engine, or propeller.
 
They seemed a bit confused about the old 10-5135 number and didn’t really have any additional information about it.
Was that a parts person or did you talk to a technical support person?
 
“Appliance” seems like another case of FAA saying “ Do what I say; not as I do”.

If anyone remembers paperADs; they had an index under each of 4 categories,

Aircraft, Powerplant, Propeller and Appliances.

If you were checking ADs on carburetors the “ Appliance “ section is where you

went.

The Lycoming O-360 A4M is used on both the Piper Archer and the 180 hp

conversions on the 172.

While the engine is the same I have my doubts if the same carb can be used in the

pressure system and the gravity system.


Any comments on why Piper lists the p/n in the Aircraft TCDS and Cessna (Textron)

does not?
 
Any comments on why Piper lists the p/n in the Aircraft TCDS and Cessna (Textron) does not?
Because, as I noted, it can be confusing at times where the line is drawn. Usually if the airframe or engine OEM does not "claim" the item it gets labeled as an appliance. In other cases like a IO-540 they claim the fuel injection on the TCDS. So it depends and requires a bit more research in some cases. No different than a Bendix mag switch. Its listed in all the airframe IPCs, yet is considered an appliance and its AD often gets overlooked for that reason as noted by others on PoA. It is what it is.
 
Ok; so it’s the same thing only different?

My concern is folks are not happy when informed they have the wrong prop,

mag or carb installed. A “Parts Person” “ rather than “ Tech Support Person “.

can have the finger pointed at them.

The “Installing Agency” still has the responsibility though.

At one time I simultaneously encountered 2 aircraft with

engines that were not approved.

One was an FAA guy.
 
I got to the bottom of it. Another call to Lycoming and mainly the one to Marvel cleared it up. Lycoming was correct in saying that 10-5135 is now superseded by the new p/n 10-5217 and that either is acceptable. They were incorrect; however, in telling me that there is an internal difference and that it “might” be best to stick with the old number just in case. Marvel tech department confirmed that the only difference is an external port in the body just above the data tag. The new number is drilled, threaded, and plugged for a temp probe. The old number is drilled and sealed (not threaded). This modification was accomplished to help mechanics from screwing up the temp probe modification. Once the modification was made the FAA required a new part number. Zero difference otherwise. Both numbers are still being made and overhauled today. The original number in the Cessna book has long since been superseded to the current numbers.
The quality difference in overall vs rebuild is still not 100% clear other than rebuild brings it up to “new” standards whereas “overhauled” is only “acceptable” standards. So many details on everything! I suppose some operations require rebuild quality instead of OH?
 
I suppose some operations require rebuild quality instead of OH?
Not that I've seen or heard. But its no different than the difference between a rebuilt engine vs an overhauled engine. Do you know if the rebuilt carb gets a TT: 0 like a rebuilt engine? But keep in mind not everyone can "rebuild" a component as mentioned in Part 43.
 
No idea if it gets zero TT but it is the manufacture. Marvel Schebler does the overhauls and rebuilds in house at KBTV. Nice shop they have. I’ve dropped and picked up aircraft at Triad engine shop next door. They get all carbs directly from Marvel. Can’t beat the service when it’s on the same field. Most items are replaced with new regardless of OH or rebuild. The shaft however, and some other lasting items get reused during OH. Sounds to me like a rebuild is absolutely as good as new.
 
Sounds to me like a rebuild is absolutely as good as new.
FYI: that's exactly the intent. Matter fact you can't legally use the word "rebuilt" unless it does meet the same tolerances as a new part. (Part 43.2)
 
Rebuilt items meet new standards for parts. Overhauled items meet in service tolerances.
 
Good info. Wonder if a rebuild engine requires a rebuilt carburetor? Only reason I can think of that they would even offer the service. Why would anyone pay for new?
$950 Overhauled
$1200 Rebuilt
$1650 new
 
Wonder if a rebuild engine requires a rebuilt carburetor?
If the carb is part of the engine TCDS as mentioned above, then it would also be required to meet the same condition.
Why would anyone pay for new?
Personal preference, etc. The same reason people pay for new, rebuilt, or overhauled engines.
 
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Is Marvel even the a supplier to Lycoming anymore? My understanding was that AvStar was the OEM supplier for Lycoming.
 
Yep. According to Lycoming both companies are supplying, are at least certified to supply.
 
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