The International Cessna^® 170 Association

Hi,

For a couple of flights now my carb heat gets stuck in the off position and may or may not work after some "fiddling." I took the cowling off and find that the bearing on the side opposite the cable connection seems to be off-center and binding. The cable and attachment are all newer and work just fine.
I see various kits for fixing this apparent problem and I also saw a what appeared to be a complete carb heat box for around $700. Anybody have experience with this problem and attempts to fix it?
Looks like it might be a poor design in the first place.

Thanks for the help

I had the same problem on my J3 a few years ago. My mechanic repaired it with a bushing, and it's been fine ever since.

John

canderson wrote:...Looks like it might be a poor design in the first place. Thanks for the help

Regardless of the design, it is the one approved for the airplane and no substitute exists that I know of. Your best solution is to repair the box, which will probably require new bushings.

best route is the repair kit made by avglas which comes with a stc, can be bought from Mc farlane. I installed one on mine a few years ago. See
http://www.mcfarlane-aviation.com/Produ ... ber=FG-105&

I just went through this last month on my annual. In my case we suspected we would need to put in new bushings. Turned out that the problem was actually the shaft itself. One side was worn 1/2 way through and the other one was about 1/3 worn through. My IA replaced my shaft with a stainless steel one w/ threads on either end. Biggest job was cutting old shaft & getting flapper/butterfly loose from old shaft. Welded butterfly to new shaft. Works fine.

Do these fixes mentioned so far entail splitting the box open or can this be done through the front opening?

I really appreciate the comments so far!

Chris-
If you don't want to do the job yourself, send it to F. Atlee Dodge, 877-332-8533, http://www.fadodge.com. They do lots of them and it will be a good repair. Not cheap but good work. They have done three for me over the years on different planes. Talk to Steve.

The kit supplied by Avglass can be installed by any A&P that can work a flame stick. I did mine a few annuals ago, when I recieved the kit it took me about two hours once I had the airbox off.

Carburetor Airbox Repairs--all makes.

Advertised in "Aviators Bulletin"

Joe Rogg (800) 244-0866, Ext.165
phone (623) 869-0866
fax (623) 780-8484

I've seen his work done on an airbox for a C-182. Excellent!
Prices unknown.

OK,

Thanks for all the replies. Here's a novice question.
Can I, being the mere owner, remove this carb heat box, without an A&P present, and send it to an approved repair facility and then replace it myself once it's fixed?
I know about the owner allowed preventive maintenance, but not having studied the other maintenance FARs, I'm not sure about some of these "what ifs."

Thanks again

Yes, you can do all that work, but before the airplane can be flown again, there must be a log entry describing what was done. That entry must be signed by a licensed A&P mechanic. So first figure out who's going to sign your log, then work it out with them how the work is going to get done.

The mechanic will probably at least want to inspect the result before signing the log, and he might only be willing to sign it if he does the work himself. Or something in-between, where you do the work under his watchful eye -- it's all up to the mechanic whose license is on the line.

Best Regards,

John

Oh boy! 3.....2.....1.....

canderson wrote:OK,

Can I, being the mere owner, remove this carb heat box, without an A&P present, and send it to an approved repair facility and then replace it myself once it's fixed?

Yes... However to legally fly it again the work would have to supervised and signed off by an A&P.

Well...yes....and ....no. You can remove it. You can re-install it. It may not be legally flown until inspected and determined to be airworthy.
Can an ordinary A&P inspect it for airworthiness for return to service? No. An A&P may supervise your work, and then he may approve it for return to service.
But you may not perform work out of view of an A&P and then it be completely legal for him to sign off your work. This is because the rule requires that an uncertificated workman must be under the DIRECT supervision of the A&P. He must be there and witness the work as it is being performed. This does not mean the A&P can come along later after the work was performed and say "it looks alright to me" and then sign it off as if he supervised the work.
To approve the return to service of an airplane that has not met the rule it must be inspected by an A&P with Inspection Authority.... (an "IA")...before it is returned to service. (This is my opinion based upon lots of research-reading and official-opinion-solicitation from the FAA. It is not the convenient answer, but I believe it is the correct one.)

I believe the amount of supervision is on a case by case basis. The A&P needs to inspect each stage of the project if it can not be adequately inspected all at once when it is done. Also how much supervision has a little to do with the ability of the person doing the work. It is up to the mechanic to determine at what stages he wants to inspect it. After all he is the one putting his name on the line for it. That has how our local FSDO interprets it. We can take any FAA reg out there and do the most conservative strictest interpretation of it and make our lives more difficult if we want but its not necessary.
Shawn