Sticky throttle

[Timothy Quigley]

I'm a relatively new co-owner of a 1966 260B with fuel injection. On a few recent flights, the throttle seems a little difficult to pull all the way out. On short final when I am pulling the throttle back to essentially idle, it sometimes hangs up a little. On the ground, during run up it sometime happens. When it does, this might mean the difference between returning to a normal idle at 500 RPM to running at 800 or 1000 instead. Every time it happens, it seems that a deliberate and firm pull straight back or resolves the issue.

Today, my co-owner flew and as he backed the throttle out on approach, it literally stuck at about 15" manifold pressure. He says the friction lock was out completely. After yanking on it pretty good, he says he pushed it forward then pulled back again and was able to get it to where he needed it (though he said it felt like there was a notch or something around where it was stuck before).

He landed without any further issues and reported the problem to our mechanic who looked at it right away. He could not repeat the problem on the ground but still inspected the throttle and cable and found no issues.

Thoughts? I'm inclined to just buy and install a new throttle control and cable but it appears the control is difficult if not impossible to find (based on my initial searches).

Any suggestions on what might cause this? Potential things to check and/or do to resolve?

Thanks in advance.

Tim
N9024P

[N3322G]

Tim,

I'm with you on replacing the control. Did all 10 control cables for the Twin to both engines. They obviously are different than yours. When I go looking for parts, I start with google and the part number and then just sit down with the list of parts providers from this website Home page and start calling.

In the meantime, other owners have used a variety of lubricants to extend the control cable life. Did all of them before replacing them all - IMHO, the extra work to lubricate was wasted $ for me.

[JIMICS2452]

It is time to replace the cable. McFarlane can build a new throttle cable.

http://www.macfarlaneaviation.com/?ID=21350627&

[Timothy Poole]

Macfarlane doesn't list a replacement throttle cable for the PA-24 by part number but perhaps they could make you one.

I would first check the cable routing/clamps forward of the firewall to make sure the cable sheath is secured and not flexing preventing your proper cable travel. If it is secured properly, you should definitely replace the cable as failure could be imminent. I would ground the aircraft regardless until it's been remedied.

Tim

[Matt Bogard]

You need new McFarlane cables. I did all three on my '59 250 because the throttle friction lock quit working and the mixture was getting sticky.

The mixture and prop controls are stock PMA parts, you can look them up on the website (mixture MC600-72 and prop MC455-184). For the throttle, I just sent them my old one and they built a new one for me, $275. I've attached the form they used to get all of the measurements off of the old throttle. My mechanic spent a day installing all three. The mixture cable was a little tricky because the retaining nut behind the panel is in a tight spot, but otherwise things were straightforward. I think we then did a 337 to put it back in to service. Night and day difference all around!!!

[Timothy Quigley]

Thanks. Will look into the McFarlane option.

Cheers,
Tim