Lycoming Engine Sputter in Flight

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MJR Pilot

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MJR Pilot
Looking for any views on a situation I encountered last night. I've owned a Piper PA-28R-200 for 3 years. Engine (Lycoming IO-360-C1C) was factory rebuilt as of June 2017 (previous owner had a prop strike so had to replace engine). Engine only has 550 TSMO. For the 3 years I've owned the plane, have never had an engine issue. Regularly maintained and change oil every 40-50 hours with clean results each time. This changed last night. I departed for a cross country and at 1,500 ft, while climbing with power/prop at 25/25, the engine briefly sputtered / hiccuped. It didn't stop completely - I can only describe it as a hiccup. This only lasted 1 - 2 seconds before it went back to producing full power and making normal sound. Mixture was full rich the whole time, and electric fuel pump was also still on. Both tanks had full fuel. Plane recently had oil changed and had 7 quarts during preflight. I returned to airport which took about 5 minutes, and then had a 2-minute taxi. During the return and taxi, the engine was perfectly normal - no issues at all. I am going to have my maintenance shop look at the plane next week, but in the interim, would welcome any views / guesses on (1) what may have happened here, (2) whether this is actually common (it's never happened to me in 600 hours of flying) and (3) what solutions might be. I know this is likely very difficult to answer without actually inspecting the engine, but would just appreciate any relevant views from folks with more expertise than my own. Obviously a bit concerned safetywise, and also hoping this doesn't mean a ton of downtime for the plane. Thanks in advance for any responses.
 
I had nearly the same experience one night taking off in the Archer. Made the hair on my legs stand up. Unfortunately, hiccups like these are very hard to replicate and ultimately diagnose. My A&P couldn’t find anything wrong. It could’ve been something as simple as passing some water, which caused an intermittent power disruption. Never hurts to let your mechanic do a full once over though. Good luck!
 
RyanB said:
I had nearly the same experience one night taking off in the Archer. Made the hair on my legs stand up. Unfortunately, hiccups like these are very hard to replicate and ultimately diagnose. My A&P couldn’t find anything wrong. It could’ve been something as simple as passing some water, which caused an intermittent power disruption. Never hurts to let your mechanic do a full once over though. Good luck!
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Thanks Ryan. Just curious - was a brief couple second sputter like I described? Did mechanic find anyything at all? Thanks again.
 
How much RPM was lost? Was the electric fuel pump still on? What were the mag drops before and after flight? Do you have an engine analyzer that logs data? What do the fuel samples look like? Has the aircraft flown since?

Very difficult to troubleshoot over the net.
 
MJR Pilot said:
Thanks Ryan. Just curious - was a brief couple second sputter like I described? Did mechanic find anyything at all? Thanks again.
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It was exactly as you described. I was probably 500-700 AGL. Fuel pump on, hand on the throttle, everything routine etc., when all of a sudden there was a sudden hiccup. I don’t remember how much RPM was lost, it happened so quickly, but I wasn’t able to replicate it again. My best guess was some water passed through the system.
 
JAWS said:
How much RPM was lost? Was the electric fuel pump still on? What were the mag drops before and after flight? Do you have an engine analyzer that logs data? What do the fuel samples look like? Has the aircraft flown since?

Very difficult to troubleshoot over the net.
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Thanks. Understand difficult to diagnose here. I don't know the RPM drop - it happened and was over so quickly I didn't get a chance to check the tach. Electric fuel pump was still on. Mixture was full rich. I did not take fuel samples post flight, but pre flight they were clean - no water, no sediment. Run up showed no issues - both mag drops were about 75 RPM, well within limits. I do have a G3 engine monitor - didn't even think to check that, so I'll do that (thanks for the reminder). I don't recall exact OAT, but well above freezing - it was in the 70s on the ground, and I was only at 1,500' when issue occurred.
 
I would guess minor water ingestion. You can sump the tanks but not get every drop of water out.
 
Thanks Joe. Water ingestion comes up a fair bit as I've researched this. I guess I would have thought any small amount of water would have passed through before reaching 1,500 feet. Between preflight sump, taxi, run up, takeoff and climb out, no issues until 1,500'. Strange. I'm starting to realize that there isn't always a perfect, definitive answer to these issues either. Thanks for your insight.
 
If it doesn't stay hiccuping it's nearly impossible to find the problem. Sometimes it's something as simple as a piece of carbon breaking off the head or piston and getting caught in the exhaust valve for a couple of cycles.

550 hours. When was the last time the injection servo fuel strainer was taken out and inspected and cleaned? It's a 200-hour item. When was the fuel strainer on the firewall cleaned? (100-hour or annual item.) Or even drained? (every preflight.) Injectors themselves been cleaned? Were the mags removed and inspected at 500 hours? That is a less likely cause, but they should be done at 500 anyway. If the carbon brush in the mag is getting chewed up, it spreads carbon dust around the distributor and flashover can occur, causing a hiccup.
 
Checking for water is routine.

How about checking for jet fuel contamination? (Tissue test)

It would seem the kerosene type fuel would dissolve in av-gas but I don’t

think that is 100 % true.

Folks using used heating oil containers to store mo-gas has this issue.

Astonishing what came out of the sump!

Heating oil, diesel & jet fuel are all somewhat similar.

There have been ADs that address the issue.

Worth a check anyway.
 
Dan Thomas said:
If it doesn't stay hiccuping it's nearly impossible to find the problem. Sometimes it's something as simple as a piece of carbon breaking off the head or piston and getting caught in the exhaust valve for a couple of cycles.

550 hours. When was the last time the injection servo fuel strainer was taken out and inspected and cleaned? It's a 200-hour item. When was the fuel strainer on the firewall cleaned? (100-hour or annual item.) Or even drained? (every preflight.) Injectors themselves been cleaned? Were the mags removed and inspected at 500 hours? That is a less likely cause, but they should be done at 500 anyway. If the carbon brush in the mag is getting chewed up, it spreads carbon dust around the distributor and flashover can occur, causing a hiccup.
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Thanks. I'm going to look into this and will discuss w the shop as well. Strainer was drained preflight - fuel appeared free of any water or sediment. Appreciate the insights here.
 
MJR Pilot said:
Thanks. I'm going to look into this and will discuss w the shop as well. Strainer was drained preflight - fuel appeared free of any water or sediment. Appreciate the insights here.
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When I preflight my ride, before I sump it, I jostle the wings. It let's me know they are not loose and it potentially causes any trapped water to move toward the sump. I also believe that small droplets of water can be trapped away from the sump and potentially shaken loose by shaking the wings.
 
Joe_B1 said:
When I preflight my ride, before I sump it, I jostle the wings. It let's me know they are not loose and it potentially causes any trapped water to move toward the sump. I also believe that small droplets of water can be trapped away from the sump and potentially shaken loose by shaking the wings.
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Thanks. I always shake the wings too, but I do it after sumping the tanks. I'll switch that order going forward - good insight.
 
I had something similar happen to me last month, I have no idea what it was, sudden sputter at about 2000 feet, I turned back and circled the airport few times to ensure it wasn’t going to die on me and then continued to my destination about 30 min away. This is the first time for me in 4 years as well. Sure got my attention.

Like Ryan , my best guess is water. Never happened since
 
Thanks all. FWIW, I just heard from my mechanic - he said the same thing - "water in the tank". That's reassuring to say the least.
 
"Water in the tank" is supposed to be trapped by the fuel strainer. If it's getting as far as the fuel servo on the engine, there's something wrong. The screen in the fuel servo is fine enough that it can stop or hamper fuel flow if water gets to it. That's why I wondered about the 200-hour servo filter check: if water's getting that far, some will be in that screen. Not a good sign at all.

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I have seen this on a lot of Archers and haven't read anything on why. My O-320 does not not seem to have that problem.
 
Dan Thomas said:
"Water in the tank" is supposed to be trapped by the fuel strainer. If it's getting as far as the fuel servo on the engine, there's something wrong. The screen in the fuel servo is fine enough that it can stop or hamper fuel flow if water gets to it. That's why I wondered about the 200-hour servo filter check: if water's getting that far, some will be in that screen. Not a good sign at all.

View attachment 100410
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Dan Thomas said:
"Water in the tank" is supposed to be trapped by the fuel strainer. If it's getting as far as the fuel servo on the engine, there's something wrong. The screen in the fuel servo is fine enough that it can stop or hamper fuel flow if water gets to it. That's why I wondered about the 200-hour servo filter check: if water's getting that far, some will be in that screen. Not a good sign at all.

View attachment 100410
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Thanks Dan. This is very helpful. I'm speaking w shop on Monday and will ask about this.
 
Carbureted airplanes struggle with water in carb bowls this time of year. How does it get there? Who cares? Add some isopropyl and get rid of it. I use iso about every third or fourth tank to eliminate water problems.
 
Your airplane’s POH should provide that info. It’s usually 1% (12oz per 10 gallons.) I’ve had great results with 12 oz per side even when I have more than 10 gallons of fuel.
 
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I’d sump em post flight after that to and see. Once on a long cross country I was in the pattern at dusk to crash on an fob couch and mine hiccuped then again… I fly a right pattern so I just said land and diagnose in AM as I had the field made when it did it.

in hind sight I should have switched tanks.

the sump the next am was cloudy, and took 5 pulls to get to clear blue glass. It was not water beads at the bottom. It sounds like it can happen in some pumps that it actually can “blend” the water and gas… after sumping till clear, I filled up- departed on the other tank and then switched to that one and burned it dry over the plane states at cruise but all went fine.

As mentioned if it’s not repetitious it’s tough so check any simple thing that can be brainstormed…
 
Had something very similar on my O-470L powered C182B on 3 out of 5 flights over a 1 month period. Very brief 2-3 second roughness/coughing like you mention. I had the mags "refreshed" (mags and engine were right at 500 hrs since overhaul) and carb overhauled (which obviously you can't do). It hasn't happened since. If it starts to happen regularly I'd look at the mags. If it's just a one-off I wouldn't worry too much.
 
Side note, my IO360 climb is at max RPMs (2700) and MP is whatever it is (full power), is OP limiting RPMs and power (25/25 comment)?
 
What was the temp? I’ve had this happen twice with my io360 both on very hot days after a previous hot start. Didn’t even flinch long enough to make the tach drop. But still got my attention.


Sent from my iPhone using Tapatalk Pro
 
Stewartb said:
Carbureted airplanes struggle with water in carb bowls this time of year. How does it get there? Who cares? Add some isopropyl and get rid of it. I use iso about every third or fourth tank to eliminate water problems.
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Be careful with isopropyl. You want to get the 100% stuff from an industrial supplier. Retail stuff is usually 70% IPA and the rest is water. You end up adding water to your tanks. And if you use it for airframe deicing, the alcohol evaporates and the water stays and freezes.
 
MooneyDriver78 said:
Side note, my IO360 climb is at max RPMs (2700) and MP is whatever it is (full power), is OP limiting RPMs and power (25/25 comment)?
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Some of the Lyc IO-360s don't have a fuel return line to the header or main tanks. A bit of air getting into the fuel lines has no place to go other than into the servo and injectors. That will definitely cause a hiccup. Turbulence or uncoordinated flight with less than full tanks can do it.
 
MooneyDriver78 said:
Side note, my IO360 climb is at max RPMs (2700) and MP is whatever it is (full power), is OP limiting RPMs and power (25/25 comment)?
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Arrow POH calls for takeoff at max RPM's and MP, and climbout to cruise at 25/25.
 
Huckster79 said:
the sump the next am was cloudy, and took 5 pulls to get to clear blue glass. It was not water beads at the bottom. It sounds like it can happen in some pumps that it actually can “blend” the water and gas… after sumping till clear, I filled up- departed on the other tank and then switched to that one and burned it dry over the plane states at cruise but all went fine.
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Water can be in fuel in three forms: Dissolved, entrained, and free. Free water is the stuff most will catch with a sample cup. It lays at the bottom in an obvious manner. Entrained is harder to catch and sometimes shows up as "snow" in fuel on a cold day. It has usually condensed from dissolved water and has frozen when the temperature dropped. Dissolved water usually causes no trouble until the temp drops, and all gasoline will have some dissolved water in it. Winter Mogas often has a small amount of ethanol in it to mix with the water and disperse it.

See this: https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC20-125.pdf
 
MJR Pilot said:
Thanks. I always shake the wings too, but I do it after sumping the tanks. I'll switch that order going forward - good insight.
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I hold the wing up for about 10 seconds hopefully to get any water to travel down toward the sumps before sumping. But I can see some logic in doing some jostling first, and then end with the 'hold.' I'll probably start doing it now that I've heard of it. I also let a fair amount of time pass after refueling. Something I learned from another pilot. Does it make a difference, I dunno, therefore I just do it.
 
Dan Thomas said:
Be careful with isopropyl. You want to get the 100% stuff from an industrial supplier. Retail stuff is usually 70% IPA and the rest is water. You end up adding water to your tanks. And if you use it for airframe deicing, the alcohol evaporates and the water stays and freezes.
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As a guy who plays with motorized toys all winter I keep a case of isopropyl around. I use it for airplanes, too. If you park outdoors in winter you know how the sumps get fouled from ice crystals precipitating out of fuel. I don’t mess with it. Isopropyl takes care of it. It does the same for condensation in fall weather. Tis the season.
 
Do the Lycoming exhaust valve wobble check, per SB388. Bet you have a valve stem that’s tight, beginning to stick.

Ream it before it sticks hard, damaging valve train and piston.

Paul
 
PaulMillner said:
Do the Lycoming exhaust valve wobble check, per SB388. Bet you have a valve stem that’s tight, beginning to stick.

Ream it before it sticks hard, damaging valve train and piston.

Paul
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His engine was factory-rebuilt in June of 2017. Lycoming changed to high-chromium-content valve guides in 1999. The previous guides had wear problems, resulting in that SB388. The SB hasn't been updated in 17 years. And after only 550 hours I wouldn't think that valve sticking should be a problem anyway.
 
Dan Thomas said:
Water can be in fuel in three forms: Dissolved, entrained, and free. Free water is the stuff most will catch with a sample cup. It lays at the bottom in an obvious manner. Entrained is harder to catch and sometimes shows up as "snow" in fuel on a cold day. It has usually condensed from dissolved water and has frozen when the temperature dropped. Dissolved water usually causes no trouble until the temp drops, and all gasoline will have some dissolved water in it. Winter Mogas often has a small amount of ethanol in it to mix with the water and disperse it.

See this: https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC20-125.pdf
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yea this was a nice temperate summer evening, but sure woke me up for the landing! :)

I’ll have to check out that advisory circular. I wonder if at higher rpm if she wudda just drank it without much todo?
 
Dan Thomas said:
I wouldn't want to find out.
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i didn’t either especially as I was headed for Wyoming and Idaho, so even though I dumped it till it was a clear blue I burnt that tank dry over Iowa and Nebraska! Just in case some was still hanging out in there..
 
Dan Thomas said:
His engine was factory-rebuilt in June of 2017. Lycoming changed to high-chromium-content valve guides in 1999. The previous guides had wear problems, resulting in that SB388. The SB hasn't been updated in 17 years. And after only 550 hours I wouldn't think that valve sticking should be a problem anyway.
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Not so, Dan... valve sticking continues due to carbon and lead salt build up, irrespective of guide wear. There's any number of online SDRs. Lycoming RE-issued SB388C five years after that metallurgy change, as the problem continued. Lycoming changed valve train component manufacturing yet again this year, according to Lycoming engineer Chris Gayman, to address ongoing durability complaints, including those from OEMs Piper and Robinson... of valve guide premature wear, among other complaints. Note that OEM complaints were at very low engine time.

Paul
 
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