Has anyone ever had carb ice shut then engine down? Engine stumbled for a second or two then off…pulled carb heat, pumped gas a time or two, the engine re-started…
Evening flight
45-50 degrees,
1000’ AGL- 2500’ Above Sea Level
Humidity 70-80%
Not raining…no visible moisture…clear evening.
80 mph ground speed…@2350 rpm
Not completely but close enough a few times. I watched my manifold pressure gauge drop then the engine slowed and coughed. Did the same thing - carb heat with gas pumping and it reignited. The accelerator pump discharge is airwise upstream of the throttle plate and if relatively warm the sprayed fuel can help melt the ice. Tough on underwear.
Gary
LMartin thanked for this post
Well it doesn't always work out with just stained under britches: Have an old friend that finally tore the fabric off his 125/18 and completely rebuilt the fuselage with bunch mods, new floorboards and glass, recovered fuselage and feathers. On the maiden flight, he took it out to see how it flew, and started looking for moose, with flaps down and around 2000 rpms, around 50 degrees with low overcast, So he did a bunch of orbits for 15 mins or so, looking until it was getting dark, He then decided to headed back to the airport. He had not checked his carb heat and not noticed any drop in his rpm's. So flying along about 150' above the trees, he had cleaned up the flaps, and went to add power to cruise, and the engine gagged a bit, so he pulled carb heat out and engine stumbled badly, tryed pushing it back in but as all this was taking place, lost nearly 100' of altitude, at this point he realized he had ALOT of carb ice and engine was running, but very rough! At this point more heat was making it worse and he was struggling to stay out of the tree tops, so in desperation he tryed the primer to bypass the carb, and that helped every stroke, but in between strokes, he was loosing altitude............ Weaving now thru the tops of the trees to the point it became obvious he needed to pull the flaps as he settled into a big hardwood tree still pumping the primer frantically, engine still running off primer in surges. He completely distroyed the Cub, but he was not seriously injured..... The Cub which was not insured was not hurt that bad on impact, but as it came down thru the branches, it sustained massive damage. There is a point with carb ice, and low altitude's that is dangerous stuff. Be safe.
E
No, but on an O-470L I've had it get rough even at cruise power settings and then get rougher as I turned on carb heat. It's to the point in winter where I just cruise around all the time with carb heat on and lean the mix to account for it, until/unless it gets below 0F on the surface (it'll usually still be about 10F at 2000-3000 with the inversions) at which point carb heat is no longer effective at keeping the carb temp sufficiently warm, and in fact might exacerbate the problem. Luckily the plane has a carb temp gauge.
This is why the new airplane I'm taking next year will have a fuel injected engine. Almost all of the engine failure accidents in Alaska over the last 20 years have been due carb ice or fuel exhaustion.
I got stupid flying my C90 Pa11 because it never once got carb ice. Had a C90 Champ that got ice and quit making noise up in the Adirondacks one morning. I pulled carb heat and turned to nearest lake 4 miles away and kept the prop spinning and after 10 or 15 seconds it stumbled a few times then ran great again. Totally my dumb fault
Glenn
"Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
Pay attention to humidity as well. Use caution early or late in the day when flying low over vegetation which generates a higher level of moisture. Think morning and early evening fogs.
https://www.boldmethod.com/learn-to-...tems/carb-ice/
N1PA
Evening flight in my 65 hp Cub last month. Landed at a small farmers strip and back taxied the runway. On takeoff at 400 feet AGL the engine started to stumble, dropped the nose and started gentle turn back towards the strip. Pulled Carb Heat and the engine ran really rough for about 2 seconds and quit. Not enough altitude to make it back to the strip, so picked a plowed field and lined up with the furrows. Made it down OK, and after pulling the seat cushions and floor boards out of my butt let it sit for 20 minutes. Started her up and flew back home. Temperature was 71 degrees, no visible moisture, but humidity was in the 80% range. I now do a carb heat check before every take off!
The O360 on 4CC has died a few times we think because of carb ice. I did not use carb heat on power reduction for years - now we do it all the time. I have had the prop stop doing power off stalls without carb heat, and upon pulling the power just before touchdown. These lightweight props (like the MT) exacerbate the problem in my opinion as there is little or no flywheel effect - or at least they make it more noticeable!
sj
"Often Mistaken, but Never in Doubt"
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Anyone who’s flown a lot in coastal Alaska likely has some carb ice stories. Fortunately, the process in the Beaver, which is equipped with a carb inlet temp guage, is to run partial carb heat continuous to keep carb inlet temp at +7 Degrees.
I had a few “interesting” carb ice episodes in the Cub. Oh, and don’t believe for a moment that you can’t get carb ice with air temps well below freezing…..
MTV
It quit at what power setting? No card heat prior to? Any noticeable loss of rpm? I’ve had an engine quit momentarily from ingesting ice after I applied carb heat but without carb heat applied? Never. I can’t imagine ice doing that without the engine running poorly before the event.Originally Posted by J5Ron
Out near the Softuk Cabin in your neck of the woods J5Ron. Low and slow having a look at things when carb heat was applied during approach to landing. Engine stumbled and quickly stopped running. Had about 7 seconds to put it on the ground as best I could. Trees or the rolling sand. Rolling sand it was. Gear leg damaged upon landing while everything else remained intact and unaffected but the wind afterwards is what really got the plane.
The 470K in my C180 has never made ice when I was flying it as near as I can tell.
I still do a carb heat rpm check as part of my run-up,
and apply carb heat for a few seconds before every takeoff.
Also apply it once in a while in cruise flight-- just in case.
OTOH a guy I know installed a 470-50 ponk engine in his C180, and got carb ice all the time.
The wrong size induction crossover tube is often blamed for carb ice-- he tried all three (?) sizes but no improvement.
He finally ended up installing a Bendix fuel injection system to solve the problem.
Cessna Skywagon-- accept no substitute!
Remember it does not always sneak up during flight time. My Super Cub will make ice while taxiing on cool wet cold grass before take-off in the spring or fall. Molly and I's rule is when the temps are below 60 and the tires are wet from the taxi we pull full carb heat on once rolling with take off power and we push it off slowly when it wants to fly.
Last edited by OLDCROWE; 09-26-2021 at 09:35 AM.
Remember, These are the Good old Days!
My dad told me a story about my grandfather flying in Alaska in a J3 back in the 60's. Said he was crossing over a lake when the engine started to stumble so he pulled carb heat but it didn't help immedately. As he was sinking towards the water he got the bright idea to reach up and flip the mags off then when then prop was slowly windmilling flip the mags back on again. The backfire blew the ice out of the intake and the engine resumed making full power.
Don't know how true it is but I always tucked that one away in case it happened to me. I'm religious about using carb heat whenever I'm low and slow and I give a minute of carb heat every 30-45 minutes in cruise just to be on the safe side. I've heard small Continentals are pretty bad about making ice.
Hmmm, I do wonder what engine you have in what plane with your story.
The reason I ask is that different engines and inductions have different results. The induction is a big deal- I had far less carb ice on my cub with the bullet filter after running a flat one for a few years... not to say it was eliminated.
Flying in Bethel the rule is to taxi to your take off with carb heat, yes- pull it on after start, then push it in as you apply take off power. Why? Because as stated above the humidity has lots to do with ice forming. Visible moisture- as in ice fog- you better expect carb ice to be happening and be vigilant.
Kirby, I have had ice at 80 degrees. Suggest maybe taxi with heat on and take it off as you apply full power.
On floats my 180 would hardly make it to the end of the pond in Juneau without carb heat pulled on. I recall one engine getting removed because the guy, not being a float guy, could not understand why he had very little take off power... but would not pull carb heat on taxi to keep the carb clear. We tried to tell him more than once.
My engine stalls due to ice have been in below freezing temps. One student had an engine stall when he pulled carb heat and the scat tube was full of ice from freeze/thaw and snow melting on his plane while sitting outside; hot air from the exhaust just collected moisture from the ice build up, supercooling the air which iced as soon as it hit the Venturi.
I use carb heat all the time. Easier on everything to use it more than less.
And test it on the ground!
I don't know where you've been me lad, but I see you won first Prize!stid2677 liked this post
How many hours on the cylinders? I had a issue with exhaust valve wear after only 500 hours, caused the same intermittent symptoms at about that RPM (plane had poor baffling and high CHT when I got it). Pull valve covers and see if your exhaust valves are covered in that milky blow-by and consider a wobble test. Guide wear will allow the valve to miss seat causing rough running or quit as valve rotates it reseats and runs fine. First time it happened I thought it was carb might be carb ice, I always pull carb heat on setup for landing but figured I might have forgot. Second time it did it I had been checking carb heat in flight and pulled it twice right before event. DENNY
For maximum carb heat temperature ....... Full power and climb to reduce airspeed. Reduced airspeed gives the air more time to heat up while passing over the heat muff and at full power the engine is producing the most heat.
N1PA
My current Cub had a Continental O-200 that made ice all the time. Tried the bikini kit on the induction with no change in carb ice. The best carb ice conditions for that carb/engine combo was flight just below an overcast layer around 50 degrees. Never had it quit but gradual rpm drop then stumble when carb heat pulled to clear the carb ice. This Cub now has an O-320 that also make carb ice but not as easily. When flying side by side with my hunting buddy his Cub does not build carb ice as quickly or a previous Cub I owned did not build carb ice as easily either. Currently using the fuel injected Cub most of the time and really like that setup with no potential for carb ice and Lean of peak EGT operation give excellent fuel mileage and cleaner oil.
LiteCub
I was told years ago about creating a backfire to remove ice. Seems the pilot had a small plane (?) that liked ice and he had a carb that permitted leaning out. Not a Stromberg apparently. He and his brother would pull mixture to almost quit to make the engine cough. Never mentioned applying carb heat. Lean mixtures burn slowly and can still be cooking in the cylinder when the intake valve opens with a fresh charge of air and fuel.
One thing to consider is not closing the throttle w/o prior carb heat. Ice on the throttle plate makes it larger in spots and might seal off the airflow that normally can pass at idle.
Gary
2350 as noted…had not used carb heat in the last 15-20 min…
[QUOTE=aktango58;811069]Hmmm, I do wonder what engine you have in what plane with your story.
0320 Wide Deck, Bracket Air Filter, 10:1 pistons, Catto Prop.
When I was doing my flight training with a C150 in the early 90's, I was returning from my x country and just started the descent from 4k ft on a humid day. The dash started shaking like crazy so I pulled carb heat and went to best glide but feared the engine was going to quit so I pushed it back in a bit to keep it running. Started looking for a place to land because it was not going to make the airport I was returning to. After 5-6 min it instantly cleared and started running fine. Partial carb heat may help if you don't think it will keep running with full carb heat if you have some altitude to work with.
From 2350 to zero without declining performance first doesn’t sound like carb ice to me. Electronic ignition? Short in the key switch?
I can only think of one time in 21 years that I know for sure my O-200 Cub has had carb ice. Funny how each airframe acts differently. That said, I always check carb heat just prior to takeoff, and routinely apply it in flight as I think of it during routine panel scan. On approach I usually apply it on base or final, and turn it off on short final. Was taught that way in the 70’s. Has worked ok for me through the years.
I was in a C150 on a overcast 5degree F day
I was going to do some stalls from 4000agl and reduced power pulled carb heat and after the engine sounding like a snow cone maker i became a glider
I finally pushed carb heatback in and got a restart at 300agl
Tried again/same result
I was still preprivate a week before my private ride and told flight instructor what happened. He said ‘lets go see whats up” and when i pulled carb heat thesnow cone machine started andhe pushedcarnheatback in and said “lets go home”.
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^^^^Maybe you warmed the induction air into the icing danger zone near freezing +-?
Gary
I tore up an Ag Cat that had a 1340 when it quit on takeoff, NTSB didn’t find internal damage on the tear down and I had plenty of fuel. I’m convinced it was carb ice, the operator said it was just one of those haunted engines and they don’t make ice. Conditions were good for it, no carb heat connected on the plane, and the engine caused 3 forced landings the year before when it would quit making power. 20+ takeoffs that day, and it was running great until it wasn’t on that takeoff.
Yep that was my thoughts. My crop duster instructor hadbeaten engine outs into me so much i was ‘almost’ disappointed when the engine fired. I had a nicelevel spotbetween snowdrifts picked out
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The Super Cub I flew regularly in Kodiak went past TBO, and I took the plane to Anchorage for a new engine.
That airplane kinda made carb ice with the old engine. It REALLY made ice with the new engine. To the best of my knowledge, nothing but the engine was changed. There was a notable difference in the occurrence of carb ice.
MTV
Carb airboxes range from new to worn out. The they all leak some hot air due to required internal tolerances. The older they get the sloppier the heat valve fits and the greater the opportunity for carb heat cables not fully closing the valve. I bet that can lead to increased leakage of heated air - partial carb heat - which might be good or might be bad depending on air temp and humidity.
Gary
Is that a thing? I always thought that was required, at least with a carb. And even with fuel injection it becomes your 'alternate air' source.
Web
Life's tough . . . wear a cup.
Definitely not a thing. Just something an old operator set in his ways did.
Then there is the doof like me who, last week as I entered the pattern, reached down to pull out carb heat. Engine stopped. I looked down and saw it was mixture I had pulled out. Shoved it back in and everything came back to normal.
Still not fully used to the airplane. The knobs are next to the throttle on both sides and they feel the same. One of those human factors things that people didn't worry about in 1946, I guess.
You're not a doof. If you do it again, yes you are. Good lesson learned, safely.
N1PA
I recently had a student do this to me in an airplane with the carbheat and mixture right next to each other and exactly the same type knob although obviously different colors. We put a McFarlane vernier mixture cable in and I hope that solves the problem��
"Often Mistaken, but Never in Doubt"
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You're not alone.
when I built my Cub I used the same type knobs side by side too. One red and the other black. On a night landing on final I pulled the mixture instead of carb heat and it got quiet quickly. Fortunately it restarted quickly too.
like SJ mentions, I changed the mixture to a vernier type and hopefully smartened up a bit.
"Fast is fine, but accuracy is everything." Wyatt Earp
I was hopping rides years ago in a homebuilt Great Lakes 2T1A powered with a 180 hp Ranger. I had a 70+ friend in the front seat. He wasn't wearing a flight helmet and his large ears were sometimes flapping in the wind. I discovered that if I used a little left rudder his right ear would flutter and visa versa for the left. I was amusing myself with his ear exercises while coming low over the west ridge of the airport and reached down and pulled the carb heat knob. Everything went silent for a few seconds till I realized my mistake.
Glenn
Now I think I'll be chuckling all morning. Distracted by ears! Thanks, Glenn.
What type of fuel? I don’t think carb heat would work very well with the engine off, except as alternate air. I have a friend that had very similar happen in a borrowed airplane that the owner had been burning ethanol unleaded in (he tested the fuel after and lots of water settled out). The engine may have swallowed a big enough amount of water to quit. It also restarted and then he needed carb heat, we assumed because the water in the fuel iced in the Venturi easier than fuel without water/ethanol.
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I put a brand new Marvel carb on my C90 at last overhaul. Flew it for a couple hundred hours last year without any incidences of carb ice. Had to get it overhauled a few months ago due to some water accumulation and rust in the accelerator pump circuit. After overhaul I'm getting carb ice pretty regularly. Haven't quite figured that one out yet.
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