Fear of Leaning the Mixture too much

CC268

Final Approach
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CC268
Alright I have come here to walk the walk of shame...I am always worried about leaning when I fly. I guess I am worried I might lean it too much and the engine might die and then the engine might not restart. I fly a 1965 Cherokee 140...O-320-E2A engine if it matters.

Help me out guys.
 
Watch the EGT needle, stop leaning when the needle reaches it's highest temp, then richen until it moves back some. How far Rich of Peak is a topic for endless discussion . . .

If you don't have EGT, lean until the engine gets rough then richen up until it's smooth again.

Don't think a Cherokee 140 will run Lean if Peak . . . .

P.S.--this is in flight, after you climb to your cruising altitude and level off. Do not try to lean before takeoff or in the climb!
 
no no....keep leaning another 30 or 40 degrees. Things will get "cooler" in that direction....go rich and your engine will heat up.

For carb'd engines....add a touch of carb heat to help fuel atomization.
 
Watch the EGT needle, stop leaning when the needle reaches it's highest temp, then richen until it moves back some. How far Rich of Peak is a topic for endless discussion . . .

If you don't have EGT, lean until the engine gets rough then richen up until it's smooth again.

Don't think a Cherokee 140 will run Lean if Peak . . . .

P.S.--this is in flight, after you climb to your cruising altitude and level off. Do not try to lean before takeoff or in the climb!

Yea I understand how to lean...I just get nervous when leaning because I think I might lean "too quickly" and cut too much fuel and have the engine quit on me...it just freaks me out a bit when I feel the engine getting a bit rough when I lean (before enriching again).
 
That is not an uncommon fear, and it leads to running over-rich. Go up to altitude on your own or with your instructor and pull the throttle back toward idle until the engine lets you know that it is unhappy by beginning to run rough. Push it back in until the engine hums again. Repeat. Again. Then pull the mix all the way back until the engine quits (the prop will keep spinning, and the magnetos will continue to supply ignition to the cylinders). Push the red knob forward and the engine will re-start. You must be comfortable when the mix is leaned until the first sign of roughness and then eased forward until the roughness goes away. I trust that you are leaning while taxiing. Do not perform these actions while taxiing because if the engine does die the plane will not have sufficient forward motion to keep the prop spinning and you will have to resort to the starter.

Back in the day, I used to kill the mixture and take the key out of the ignition just to show my students that it was not the end of the world.

Bob Gardner
 
That is not an uncommon fear, and it leads to running over-rich. Go up to altitude on your own or with your instructor and pull the throttle back toward idle until the engine lets you know that it is unhappy by beginning to run rough. Push it back in until the engine hums again. Repeat. Again. Then pull the mix all the way back until the engine quits (the prop will keep spinning, and the magnetos will continue to supply ignition to the cylinders). Push the red knob forward and the engine will re-start. You must be comfortable when the mix is leaned until the first sign of roughness and then eased forward until the roughness goes away. I trust that you are leaning while taxiing. Do not perform these actions while taxiing because if the engine does die the plane will not have sufficient forward motion to keep the prop spinning and you will have to resort to the starter.

Back in the day, I used to kill the mixture and take the key out of the ignition just to show my students that it was not the end of the world.

Bob Gardner

Wow I wish you were my instructor! That sounds like a good excercise (scary as hell though!). It's good to know that now though.
 
Alright I have come here to walk the walk of shame...I am always worried about leaning when I fly.

You mean you lean when you're in a turn? That's pretty normal as a student for the first few hours. You'll grow out of it. ;)
 
You mean you lean when you're in a turn? That's pretty normal as a student for the first few hours. You'll grow out of it. ;)

Except I'm not a student pilot anymore :(...but still a newb with only 66 hours. Off topic but I'm gonna do the emergency recovery/spin training/ aerobatics course at chandler aerobatics in a few months and then on to my instrument rating. I wanna be as safe as I can be!
 
You are in a 140.

You should be leaning until the engine runs rough. Then push it back in a hair until it's smooth. The engine is not going to die.
 
You are in a 140.

You should be leaning until the engine runs rough. Then push it back in a hair until it's smooth. The engine is not going to die.

I know its a silly thing lol
 
Yup. Seriously though, once you do some spins, if stalls scare you now they won't after spinning. A good thing and good training..
 
Yup. Seriously though, once you do some spins, if stalls scare you now they won't after spinning. A good thing and good training..

Yea power on stalls always freaked me out so I just want to go up and get nuts in the Great Lakes biplane. I think I would like aerobatics, but I am really doing it just get super comfortable in all attitudes :).
 
Yea power on stalls always freaked me out so I just want to go up and get nuts in the Great Lakes biplane. I think I would like aerobatics, but I am really doing it just get super comfortable in all attitudes :).

Just don't try to recover on a heading using the DG. Don't ask how I know that.
 
I think what I really need to do is go up spin that sucker, cut the mixture, and recover...just knock it all out at once (just kidding) lol
 
You are in a 140.

You should be leaning until the engine runs rough. Then push it back in a hair until it's smooth. The engine is not going to die.
This.

I've had engines suddenly quit while trying to lean on the ground, but never in flight. The engine isn't going to die on you in the air. Just run rough until you enrich enough to make it smooth again.

You aren't going to hurt the engine in a 140 by leaning it.
 
They restart, do multi training with a shutdown, if it's a healthy airplane you're fine.

So, a friend of mine was flying for a DZ, once of the SOP as to pull the prop back just before jump run, normally off ear as you're watching the jumpers and making sure one is on jump run, well this friends hand was not on the blue knob, it was on the red knob, turning for effect, **** her down for half a heck, pushed it back it in and all was well, kinda cured that worry.

I personally run ROP, I lean near book numbers, then I tune based on CHTs, but I like ROP for the power and a few other reasons, not many bush planes run LOP.
 
Actually if you're still rolling down the runway and accidentally pull the mixture back too much, you can get it restarted without the starter. ;)
 
Yup. Seriously though, once you do some spins, if stalls scare you now they won't after spinning. A good thing and good training..
Great answer to the OP's question. He asks about leaning, you got him spinning. SHeeeezz
 
Lean it slowly, if it starts to die, just push it back in. It won't stop running without running rough first. Don't worry, you'll get used to it.
 
Well I'd screw it back in not just go full rich
 
Great answer to the OP's question. He asks about leaning, you got him spinning. SHeeeezz

Go back to post #8 grumpy, he is preparing to take spin and aerobatic training. Typical Tom Terrific! :rolleyes:
 
Back in the day, I used to kill the mixture and take the key out of the ignition just to show my students that it was not the end of the world.
I'm pretty sure I just heard a collective "GASP" coming from the direction of the FAA building in OKC :)
 
How are you leaning? By a tach or EGT?

Even if you were to "lean too much" you'll know very quickly as the engine will start to run very rough, if it doesn't die. Back in the early days, I leaned it too much on a XC and the engine quit momentarily until I enriched the mix once again and she fired right back up.

As long as the prop is still windmilling, the engine will instantly start again once fuel is added to it. It's a common fear but nothing to worry about!
 
Go back to post #8 grumpy, he is preparing to take spin and aerobatic training. Typical Tom Terrific! :rolleyes:
What does that have to do with his question? RTFQ You are one of the people here that renders this page useless for trying to learn from asking a question. every thread gets de-railed.
 
Remember EGTs are a far second to CHTs.
 
So there I was, a long time ago in a galaxy far, far away.... a brand new student pilot who owned my own plane, out flying around in the practice area at HMT.

As I prepared to set up to practice maneuvers, I reached down and pulled the carb heat back prior to reducing power. Immediately, the engine quit.

I learned several valuable lessons that day.

1. I respond by the book to emergencies. Immediately and simultaneously pitching for airspeed while determining where to land.
2. It's impressive how the plane just kind of sits there and doesn't fall out of the sky.
3. Always 'Fly the Plane' first, worry about the other stuff (troubleshooting) after you've got the flying under control.
4. Always, touch, then identify and what the heck, identify again BEFORE applying the action.
5. The prop will continue windmilling (As long as you maintain airspeed)
6. Engines make a whole lot more noise with the mixture in.
7. With the prop windmilling, the engine will start right up as soon as you increase mixture.

I like Bob's suggestion. Go out and do it. If you're not comfortable, take a CFI who is. Just make sure you have the altitude and a good place to land. It's really no biggy.

Later on, I would frequently have friends who would fly with me, but were still a little afraid that if the engine quit, we were going to fall out of the sky.

While climbing up to altitude, Id talk to them about how well the plane would glide, and then point out in the distance about 20 miles away and say, "See that dry lake bed out there... If the engine quit right now, that's where we'd land".

As they argued with me in disbelief, I'd reach down and pull the mixture.

Each one of them was impressed beyond words and they never again feared the plane was going to fall out of the sky.

PJ
 
What does that have to do with his question? RTFQ You are one of the people here that renders this page useless for trying to learn from asking a question. every thread gets de-railed.

Have you had a bowel movement yet grumpy? Here's a thought, put me on ignore. Easy peasy.
 
OP: not to feel badly about it. I have a similar fear, at over 1000 hours: I've never gotten up the gumption to run a tank dry to calibrate my fuel stick. Too afraid the engine won't restart when I switch tanks.

As others have said, leaning will not cause the engine to die, and even if you do accidentally kill it, it will restart immediately when you push the mixture back in as long as there's fuel, and the engine and ignition system are healthy. I've run my plane to within a fraction of a gph of having the engine die when doing the GAMI lean test, and now always run LOP when at sufficient altitude to do it safely.

Best of luck overcoming this fear.
 
Back in the day, I used to kill the mixture and take the key out of the ignition just to show my students that it was not the end of the world.
I'm just picturing you dropping the keys and having them fall behind the rudder pedals
 
Have you had a bowel movement yet grumpy? Here's a thought, put me on ignore. Easy peasy.
That post simply demonstrates that you can't add any thing constructive to any thread.
 
tell us how we can repair an oil door....by soldering.....please do.
Didn't you say that aluminum couldn't be soldered? then get proven wrong? Re-read the thread. No where did I say the door could be soldered. Trying to spin it to be my statement when you were the only one hung up on the solder issue
 
tell us how we can repair an oil door....by soldering.....please do.
Here's another guy who can't stay on topic. one of the biggest violators of common courtesy on the page.
 
I'm just picturing you dropping the keys and having them fall behind the rudder pedals

I can't quite picture how holding a key in my hand for a few seconds translates to dropping it. The key was never more than an inch or two from the ignition. Sorry that I can't see the emoji but I'll bet that it is a real knee-slapper.

Bob
 
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