Continental O-470 proper throttle connection.

[maverickps]

Where can I find the reference material or documentation that describes the proper way to connect the throttle cable to the throttle valve arm?

I had a mechanic swap in an overhauled carb and looks like he forgot either the castle nut, cotter pin, or both. During runup the throttle went full open as the cable came disconnected from the throttle. On opening the cowling we found the picture below. A different mechanic says the bolt/washer/nut were put on the wrong side to begin with and reversed them as shown in the second picture.

Just wondering where I can find a diagram that shows the correct placement of washers and nuts, thanks!

 

[Ryan Klems]

This will usually be spelled out in some combination of the Maintenance Manual and Parts Manual, also sometimes there will be service bulletins (or even an AD, though none come to mind) changing the way they should be connected. For example early 182s did things one way (solid bolt with lock nut), then later ones did it another (drilled bolt, castle nut + cotter pin) and a SB came out suggesting changing to the other way on earlier models (SE79-6). For other situations where it is not clearly shown, as long as the manufacturer is still in business, I've had good luck getting drawings showing the factory stack up. Here is a picture from one of the 182 IPCs showing the installation. The large body washer is there to keep the whole assembly from disconnecting if the rod end ball were to no longer be retained by the rod end. Also, that's pretty ****ty that they failed to secure the cotter pin, glad the failure occurred on the ground.

 

[maverickps]

So acco

This will usually be spelled out in some combination of the Maintenance Manual and Parts Manual, also sometimes there will be service bulletins (or even an AD, though none come to mind) changing the way they should be connected. For example early 182s did things one way (solid bolt with lock nut), then later ones did it another (drilled bolt, castle nut + cotter pin) and a SB came out suggesting changing to the other way on earlier models (SE79-6). For other situations where it is not clearly shown, as long as the manufacturer is still in business, I've had good luck getting drawings showing the factory stack up. Here is a picture from one of the 182 IPCs showing the installation. The large body washer is there to keep the whole assembly from disconnecting if the rod end ball were to no longer be retained by the rod end. Also, that's pretty ****ty that they failed to secure the cotter pin, glad the failure occurred on the ground.

So according to your diagram, mine is now backwards and the bolt should be the other way around with the castle nut on the inside then?

 

[Ryan Klems]

So according to your diagram, mine is now backwards and the bolt should be the other way around with the castle nut on the inside then?

Assuming you have a 182 covered by that IPC drawing, it would appear so. However, so long as there is not a clearance/interference issue, it likely would not cause any issues installed that way.

 

[Bell206]

Where can I find the reference material or documentation that describes the proper way to connect the throttle cable to the throttle valve arm?

What specific model aircraft and year?

 

[Magman]

It seems to me that AD 86-24-07 specifically addresses this

on most Cessnas.

 

[Dan Thomas]

So according to your diagram, mine is now backwards and the bolt should be the other way around with the castle nut on the inside then?

The nut and cotter pin are a lot easier to inspect when they're outboard of the lever than when they're inboard.

 

[bnt83]

Looks wrong to me. The washer under the nut should be tight on the wire, and the wire needs bent into a hook to prevent it from being pulled out of the bolt if it slips

 

[Dan Thomas]

View attachment 133457

Looks wrong to me. The washer under the nut should be tight on the wire, and the wire needs bent into a hook to prevent it from being pulled out of the bolt if it slips

The washer IS tight on the wire at the washer's hole. The whole thing is a bit too tight, as the wire is bent up enough to be scraping on the lever.

 

[camorton]

Like Dan said, it doesn't matter which way the bolt goes. I've personally never seen a 182 where the nut wasn't on the outboard side (like your photo). It's just so much easier to install that way.

The important points are that there is a large area washer installed (in case the rod end fails) and that there is a castle nut and cotter pin installed. I believe your mechanic forgot to install the cotter pin and the nut backed off. It's really the only way this connection can fail as you described.

A couple of additional notes: when rigged right, there should be no contact between the rod end and the area washer. In your pic, I can see marks on the washer where it looks like it was rubbing. Also, there should be no rotation of the bolt in the throttle arm. All rotational movement should occur in the rod end bearing.

 

[Dan Thomas]

A couple of additional notes: when rigged right, there should be no contact between the rod end and the area washer. In your pic, I can see marks on the washer where it looks like it was rubbing. Also, there should be no rotation of the bolt in the throttle arm. All rotational movement should occur in the rod end bearing.

Yes to all of that. The rod end should also not rub on the throttle arm, Sometimes one needs a thin washer between the rod end and throttle arm for clearance. It depends on the lateral angle of the cable, if any, and whether the rod end has a thicker section to its threaded boss.