Mixture cable disconnected from mixture control arm. M20F

[Yannis]

I’m a new Mooney owner and yesterday while I was trying to start the engine I had no luck. I thought I flooded the engine I noticed that there was no fuel flow.

The battery got depleted, charged it overnight.  
Next day went back to try to start the engine but no luck. 
 

We decided to open the engine cowling with the help of an engineer and we found that the mixture cable connector has been disconnected.

A bit of a sobering experience but better to find this issue on the ground and get it sorted. 
 

Here is a photo of the cable, I think that the pin on the top head of the connector head got off or wasn’t there on the first place so the screw got loose and disconnected. 
 

I was able to connect it back and the engine started fine. I’m waiting for my mechanic to come and fix it properly and sign it off, maybe he needs to charge some part but is worrying that the cable would disconnect. 
 

 

[mike_elliott]

THats the old style rod end for your mixture cable. THere is an SB on it and a kit to replace the "mayPop" rod end. As you now know, when, not if it will pop off is the question.

Edited May 3, 2023 by mike_elliott

[KSMooniac]

As Mike mentioned, you ought to replace this with the newer style.  My '77 J had that originally, but I upgraded to the modern rod end style.  A couple years later during a formation flying clinic, we had an F visit and the same thing happened to him.  Fortunately I never throw anything away and was able to find my old part and help get him back in the air, but encouraged him to upgrade.  This is the kind of single point failure that can kill you.

[EricJ]

+1 that that should be replaced with a spherical rod end.    What you have is known to have a failure mode of falling off.   Changing the rod end is pretty easy and not expensive.

 

[N201MKTurbo]

Your rod end is missing it’s cotter pin. You need to screw the button at the end in until it is tight enough so it won’t come off, and loose enough so it doesn’t bind. Those two settings overlap sometimes. Then put a cotter pin in to keep it from unscrewing.

As others have said, a standard rod end is more reliable, but if you rigged this one right, it will get you by till the new parts come in.

[Denis Mexted]

My Dad had this in our old Bonanza. It had the ball rod end, but a used, in in this case 'used' metal lock nut instead of a castellated nut and split pin.

Actually in typing this I think it was the throttle. And in that case the throttle arm has a spring on it to move it to full throttle. 

What does the mixture arm do? Stay in the same position I assume.

 

[carusoam]

While we are discussing engine controls…

Losing any of them inflight can be a bit disastrous…

Engine controls have moved up the expected life list as something to be changed at each engine OH…

That is about every 2k hours of operation…

When they fail… they typically give a small amount of warning before jamming in place…

other signs of wear are often picked up during the annual…

 

So….

review the other ones while you are in there…

Getting new engine controls is as easy as it gets… owner supplied parts rule.  (Real parts, no middleman.)

Best regards,

-a-

[Huckster79]

Is there a specific nane for the newer style? My F is in for annual right now, I’d order one to have done while apart, but don’t want to order the wrong one as in a new but the less reliable style… just the end or the whole control?  If it’s been changed since new would there be a certain part number to see if it’s the new better one? 

 

So they aren’t spring controlled to full rich if the control linkage falls off evidently? 

Edited May 4, 2023 by Huckster79

[Alan Fox]

Just use a rod end with 8/32 threads , two small spacers , and a large area washer for redundancy ,  also check the trrottle link also..   You got very lucky...anybody that knows this is on thier plane , and hasnt converted is just plain stupid... Now that you know , do it right...

[Browncbr1]

When you get the rod end, iirc 10/32 female threads, add a large washer under the castle nut.  That way, if the ball ever pops out of the rod end shell, your mixture control won’t be lost completely. 

[Hank]

28 minutes ago, M20Doc said:

I know that you’re inventive and cleaver, but I want to see you thread an 8-32 rod end on to a 10-32 cable!!

You just have to push it hard enough . . . . .

[Alan Fox]

16 hours ago, Hank said:

You just have to push it hard enough . . . . .

Texas metric...

[Huckster79]

Why are they not setup with a spring to go full rich if it’s disconnected? I though, maybe wrongly, that that’s how airplane carbs are setup? 

[EricJ]

2 hours ago, Huckster79 said:

Why are they not setup with a spring to go full rich if it’s disconnected? I though, maybe wrongly, that that’s how airplane carbs are setup? 

If you're climbing out from a high DA airport that could kill you.    There's no best way to do that.

[Huckster79]

4 hours ago, EricJ said:

If you're climbing out from a high DA airport that could kill you.    There's no best way to do that.

 Be better than vibrating/wandering out to full lean… that’s a guarantee to kill regardless of DA. 

[PT20J]

The reason it doesn’t do that is probably because the Bendix pressure carbs didn’t do that and the Bendix RSA design is derived from the pressure carbs from the radial engine days.

[davesly]

Does anyone have a picture of what the new Mixture and Throttle cable end should look like (preferably connected).  I have included a pic of mine (new cables are coming) and I want to set it up correctly.

[EricJ]

On 5/26/2023 at 7:52 AM, davesly said:

Does anyone have a picture of what the new Mixture and Throttle cable end should look like (preferably connected).  I have included a pic of mine (new cables are coming) and I want to set it up correctly.

Here are two examples of how not to, but show the general idea.   The large, plastic washer should go on the outside of the rod end so that if the ball pops out of the rod end the washer captures it.   The cotter pin should capture the nut rather than be completely outside it.

 

[Fly Boomer]

1 hour ago, EricJ said:

The cotter pin should capture the nut rather than be completely outside it.

I read this multiple times while looking at the first picture ,but didn't understand.  When I got to the second picture, all was clear!

[davesly]

Someone me mentioned an SB on this.  Do you know where to find it?  Also is there a part listing for the bolt, nut, washers, spacers and rod end anywhere?  Someone mentioned a kit?

 

Edited June 2, 2023 by davesly

[Alan Fox]

13 hours ago, davesly said:

Someone me mentioned an SB on this.  Do you know where to find it?  Also is there a part listing for the bolt, nut, washers, spacers and rod end anywhere?  Someone mentioned a kit?

 

These are standard mil spec parts , I will make kits for 50 dollars each...

[davesly]

13 minutes ago, Alan Fox said:

These are standard mil spec parts , I will make kits for 50 dollars each...

Sold!  I need Mix and prop for both M20C and M20F

[Alan Fox]

On 6/3/2023 at 8:50 AM, davesly said:

Sold!  I need Mix and prop for both M20C and M20F

Call me 856 419 5209 

[davesly]

On 5/3/2023 at 5:35 PM, mike_elliott said:

THats the old style rod end for your mixture cable. THere is an SB on it and a kit to replace the "mayPop" rod end. As you now know, when, not if it will pop off is the question.

Do you know the number of this Mixture rod end SB?  I am trying to locate it for the AP/IA to put in my logbook now that it is replaced?  Thx