M20Doc please visit the creek (throttle cable issue)

[Jim Peace]

I had Daytona Beach Aircraft Service, MSC, replace my 50 year old throttle cable with a new McFarlane a couple of years ago.  It was a problem child right from the first flight.  They did not install it correctly and caused a total throttle disconnect during the first flight and many issues since.  Just today a person doing his commercial training in my plane could not get the throttle to go below 1600 RPM.  They de-cowled it and found this.  

I broke off my relationship with DAS this year after two attempted murders and a very embarrassing day they provided  me.  

Any suggestions M20Doc?  I am willing to get another new cable but my real problem is finding someone who knows WTF they are doing....So hard to come by with shops today.

I don't even know if what they did is legal.

Thoughts? feel like traveling to palm trees?

 

[chriscalandro]

I’m a little lost how it’s moving like that. 

[1967 427]

Jim sorry to hear about your plight.  It makes me appreciate the A&P /AI that does the majority of my work.  Yours is not the only story that I think we have read on this site.  One of the shops on my field (now out of business) was notorious for hiring mechanics off the street that had no aviation background.  They would do the work and one certified mechanic would review and there AI would sign off.  I always thought this was insane.  Pilots pay a lot of money because I am expect an expert doing the job.  Now, in no way am I suggesting that’s what happened at the service center that you went to, but it sure makes you wonder.

[Guest]

Jim,

The clamp should be an AN742-5, it’s a steel clamp with no rubber insert.

Clarence

[Nukemzzz]

Looks like the clamp isn’t tight enough on the cable.  Cable itself might be fine...unless it’s binding inside, or kinked, and that contributed to it coming out of the clamp. 

[carusoam]

That little rubber collar that was used initially has moved, it used to occupy space that is now slop...

Once the collar got pulled out, the slop was the only thing left...

1600rpm may or may not be enough to limp home... depending on weight... better to have too much power...

PP thoughts only, great report Jim!

Thanks for sharing it...

Best regards,

-a-

[RLCarter]

2 hours ago, carusoam said:

That little rubber collar that was used initially has moved, it used to occupy space that is now slop...

Once the collar got pulled out, the slop was the only thing left...

1600rpm may or may not be enough to limp home... depending on weight... better to have too much power...

PP thoughts only, great report Jim!

Thanks for sharing it...

Best regards,

-a-

I think the black rubber piece downstream is the dust boot for the inner/outer cable..... it’s late and I’m on my phone

[skykrawler]

Once those clamps have been pried open a couple of time they lose their shape.  Also.....the clamp required for the OEM cable may be different than the McFarlane that you now have.    Measure the cable at the attach point with a caliper to make sure -5 is correct size (5/16 inch I think).    No rocket science here.

https://military-fasteners.com/clamps/loop+clamps/AN742-5

[N201MKTurbo]

The clamp is rotating too. You should put a washer behind the nut so it clamps to the bracket.

[47U]

While you’re verifying the clamp is the correct size, you might try moving the clamp forward to the unswaged portion of the cable end.  Swaging reduces the circumference slightly.

Obviously, this will change the rod end adjustment on the carb.

[takair]

I’ve used safety wire across the clamp, such that it loops around the cable at the narrow sewage point.  It provides an extra level of security.  Can’t recall where I found that technique, but it would have helped in this situation until it would be found at some inspection interval.

[jamesm]

I have started to removing the 53yr old throttle cable with the mcfarlane purchased  through lasar.

I would like to Know what others have experience With Mooney's mcfarlane Throttle cable?

I had mine  slip on me many years ago. the throttle was stuck at 1400 rpm. It took me 2 times around the Patten before I realize what the problem was. Since   I hadn't flown in about 3 months I thought it was me. but I figured by using mixture Control To pulse power Output  I could deplete excess energy and land. Similar to what the German's did in WWII with the v2 buzz bombs to control their thrust vector.

I noticed on other Mooney's that people had safety wired around the AN742-5 clamp.

I would like Know others opinions that have replaced mcfarlane Throttle cable and experience please advise,

Thanks,

James '67C

[RLCarter]

7 hours ago, takair said:

I’ve used safety wire across the clamp, such that it loops around the cable at the narrow sewage point.  It provides an extra level of security.  Can’t recall where I found that technique, but it would have helped in this situation until it would be found at some inspection interval.

My E and 172 both have safety wire wrapped in a figure “8”? around the control cable clamps..... I figured it was standard practice seeing how they were maintained by 2 different people originally 

[Nukemzzz]

21 hours ago, jamesm said:

I have started to removing the 53yr old throttle cable with the mcfarlane purchased  through lasar.

I would like to Know what others have experience With Mooney's mcfarlane Throttle cable?

I had mine  slip on me many years ago. the throttle was stuck at 1400 rpm. It took me 2 times around the Patten before I realize what the problem was. Since   I hadn't flown in about 3 months I thought it was me. but I figured by using mixture Control To pulse power Output  I could deplete excess energy and land. Similar to what the German's did in WWII with the v2 buzz bombs to control their thrust vector.

I noticed on other Mooney's that people had safety wired around the AN742-5 clamp.

I would like Know others opinions that have replaced mcfarlane Throttle cable and experience please advise,

Thanks,

James '67C

I did my throttle and mixture a few months back. Keep very close track of the cable routing and mounting behind the dash. Also, the new cable may require that you drill the panel mount to a larger diameter and actually with a higher centerline than the prior or the cable shaft retaining nut behind the panel. I can’t remember for sure if that was the throttle or mixture. 

[mike_elliott]

10 minutes ago, Nukemzzz said:

I did my throttle and mixture a few months back. Keep very close track of the cable routing and mounting behind the dash. Also, the new cable may require that you drill the panel mount to a larger diameter and actually with a higher centerline than the prior or the cable shaft retaining nut behind the panel. I can’t remember for sure if that was the throttle or mixture. 

A simple way to ensure correct routing (assuming it is correct as currently installed) is to fasten a 50# monofilament fishing line, or an electricians pull line to the old unit prior to removal. Then use this line to pull the new one back in.

 

[jamesm]

Here is how I solved the problem

Edited January 2, 2021 by jamesm

[drdpir8]

On 12/28/2020 at 6:52 PM, M20Doc said:

Jim,

The clamp should be an AN742-5, it’s a steel clamp with no rubber insert.

Clarence

Do you have the page between these two?  I'm looking for the part number of 36-4.  Same issue on a fuel injected engine.  Thanks!

[Guest]

2 hours ago, drdpir8 said:

Do you have the page between these two?  I'm looking for the part number of 36-4.  Same issue on a fuel injected engine.  Thanks!

This one?