Replacing original throttle, mixture, and prop cables

[Bob_Belville]

4 hours ago, salty said:

SB is service bulletin. I tried to find it again quickly and couldn’t. If I do I’ll post it. It may not have been a mandatory bulletin.  

While my posts are not considered "mandatory", I have pointed out to MS folks on several other threads that McFarlane recommends control cable service life should be thought of as about the same as max. engine TBO. I usually make the comment when someone posts a pic of their panel and the knobs look like 50 year old originals.

"Recommended Service Life Due to the criticalness of engine controls and considering their operating environment the maximum recommended in service time for McFarlane engine controls is equal to the maximum time between engine overhauls as recommended by the engine manufacturer."

https://www.mcfarlaneaviation.com/media/documents/control-eligibility.pdf

[salty]

43 minutes ago, RobertGary1 said:

I don’t think there’s is such a thing as a mandatory SB unless you meant to say AD. 

-Robert

Well, the title of the document is "Mandatory Service Bulletin". It is not mandatory from a regulatory perspective. For example, here's one I have handy related to the overhaul. This is the one I was thinking it was on, but it is not.

Edited March 20, 2018 by salty

[carusoam]

That sure is confusing to the ordinary PP...

I thought I would see star washers under the magneto fasteners for mandatory replacement on the top of the list...

Maybe it is further down, on a separate list of things that are really going to ruin a pilot’s day...

More reasons to have a good relationship with the people maintaining your bird.

PP thoughts only, not a mechanic or lawyer...

Best regards,

-a-

[salty]

3 minutes ago, carusoam said:

That sure is confusing to the ordinary PP...

I thought I would see star washers under the magneto fasteners for mandatory replacement on the top of the list...

Maybe it is further down, on a separate list of things that are really going to ruin a pilot’s day...

More reasons to have a good relationship with the people maintaining your bird.

PP thoughts only, not a mechanic or lawyer...

Best regards,

-a-

The third bullet is "All lock washers..."

[chrixxer]

Assuming I should do the cables while the plane is apart for engine overhaul. 1969 M20F with the throttle quadrant. What do I need and where do I buy 'em?  

[ArtVandelay]

9 minutes ago, chrixxer said:

Assuming I should do the cables while the plane is apart for engine overhaul. 1969 M20F with the throttle quadrant. What do I need and where do I buy 'em?  

McFarlane, remove old cables and send to them or measure them (I would call to make sure they’re open and if they still work this way).

[Bob_Belville]

McFarlane seems to be doing business as usual, I get regular email promotions from them. Great company. I removed cables to get good measurements to fill out their forms. A little quicker and saves shipping hassle. 

[chrixxer]

Thanks. Approx. cost? ( looks like about 200 per cable for the push/pull, but what about quadrant throttle?)

[drapo]

«If you have to ask, you can't afford it» 

Just did mine, while overhauling the engine also. Sent the specs to McFarlane and it ended up costing me $400US per cable. It was the standard panel type but should be about the same.

[carusoam]

I got new macfarlane cables when my engine got remanned... about eight years ago...

Having controls stop working can be a bummer... depending on their position when they malfunction...

Best regards,

-a-

[Matt_AZ]

I replaced my carb at annual. Figured I’d go ahead and replace the throttle & prop cable too. Glad I did because I found this: 

 

[carusoam]

Awesome detail, Matt!

Thanks for sharing that one...

Which control was that?

Best regards,

-a-

[Matt_AZ]

Just now, carusoam said:

Awesome detail, Matt!

Thanks for sharing that one...

Which control was that?

Best regards,

-a-

That was the throttle cable. After replacing the carburetor, the throttle didn’t “feel” right once it was all back together. I wasn’t happy with the way it felt, so the mechanic suggested replacing the entire throttle cable. It’s actually split much more than what is shown. 

I learned that if it doesn’t feel right, it probably isn’t. 

[carusoam]

Training always circles around the throttle braking at WOT....

Controlling power is a mixture only kind of solution... fully workable this way...

What happens if the throttle cable falls apart as you pull it back approaching the airport... form miles a way...

 

+1 for checking any odd signs you feel from any engine control... they have a way of deteriorating without telling anyone... 

Best regards,

-a-

[Hank]

McFarlane made a new Carb Heat cable for me five years ago. The old one got hard to move, then failed wide open when I checked it at runup. The only symptom was anemic climb leaving a short mountain strip going home (2770 x 30), must have been all of 100' agl as I passed the end of the runway, thankfully going downhill. Rebuilt the carb heat box due to failed hinge, but replaced the cable too, because it was still pretty stiff. You know you have a problem when Center asks if you're really a Mooney . . . .

If you're OHing the engine, get four new cables. Yes, I have the quadrant, but the carb heat is down below it. Replace 'em for peace of mind.

[chrixxer]

14 hours ago, Hank said:

McFarlane made a new Carb Heat cable for me five years ago. The old one got hard to move, then failed wide open when I checked it at runup. The only symptom was anemic climb leaving a short mountain strip going home (2770 x 30), must have been all of 100' agl as I passed the end of the runway, thankfully going downhill. Rebuilt the carb heat box due to failed hinge, but replaced the cable too, because it was still pretty stiff. You know you have a problem when Center asks if you're really a Mooney . . . .

If you're OHing the engine, get four new cables. Yes, I have the quadrant, but the carb heat is down below it. Replace 'em for peace of mind.

Hmm, I have a feeling if I try to replace the carb heat cable, my A&P might refuse to work with me again...

 

[David_H]

18 hours ago, chrixxer said:

Thanks. Approx. cost? ( looks like about 200 per cable for the push/pull, but what about quadrant throttle?)

I replaced the mixture cable (75F with quadrant) last year. This was done with the engine installed and the work was inspected and signed off by an AI. Notes are below.

• The Quadrant Mixture Cable cost was $325.00 + shipping/handling from McFarlane.
• The Quadrant control cable manufactured dimensions have to be correct on BOTH SIDES of the system and there isn't much adjustment available to compensate for measurement or manufacturing errors.

1. If your cables are still good, USE YOUR CABLES to fill out the manufacturing form.
2. The cables manufactured by McFarlane are not "exactly" like the originals and there are slight differences that can sometimes affect the adjustment available to set the total cable throw (full rich - full lean). That is not to say the product is of poor quality though. The cables are probably better quality than the originals.
3. If you decide to ship your cables to McFarlane to manufacture to... make certain they return your original cables to you so you can verify the new cable was manufactured correctly. If the cable doesn't have sufficient adjustment available, you'll need the original ones to track down the point of error.
4. If your cables are bad enough that accurate measurements cannot be made, You will need to take the needed measurements to fill out the manufacturing form.

The cable quality was good. McFarlane makes a nice, simple product.

The customer service wasn't very good. I would honestly search for another manufacturer if I needed to replace another control cable.

Edited April 25, 2020 by David_H
grammar