O200 rough, failed runup

GeorgeC

GeorgeC

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GeorgeC
Went to fly the 162 today. I was the third renter of the day. OAT about 80F, dewpoint about 65F.

Dipstick read low, added a quart, then it read 4.5, good to go. Topped off the gas and preflighted as usual.

Started up and engine ran very rough and would only hold about 600rpm, and something smelled unusual. Strike one; shut down. Tried to start again but was unable. Strike two. Decided it was time to talk to the FBO. Guy came out and must have said a blessing, because it started right up and ran great. Did a quick mag check at 1000rpm, seemed ok on either. Leaned for taxi, radio check, and off to the runup area I go.

Push in the throttle for the runup and we're back to rough running. I called it quits at that point and could only limp it about halfway back to the tiedown. FBO guys claimed to see wispy white smoke and asked me to shut down. I pull to ICO, engine surges and runs great for a few moments and then quits.

I'm sure glad that it failed on the ground. I'm very interested to learn the root cause.
 
Too rich taxi caused fouling of plugs would be my guess. Most people don't know how to lean for taxi properly. I fly with a guy that flies at 2500 feet all day long in a C172 at 2400 RPM. His GPH is hovering around 14-15 gallons per hour. I lean it out to about 10 and it runs much better. He never leans for taxi either. It is full rental mixture and power for him most of the time.
 
Sounds like it was being run way too rich and you gunked the plugs up.

Also isn't your run up sposed to be a little higher than 1,000rpm?
 
I would send the carb. Out to a good shop for a rebuild and not let local mechanics touch it other than to take it off and put it back on.
 
Unless you're leaning to the point of the engine nearly dying, you're doing nothing at idle/near idle settings on the O-200.
 
The O-200 is an icing fool. Ice breaking off, melting, and reforming is a hallmark of this little sucker. Try taxiing with full carb heat and see how it goes.

Jim
 
Jimmy cooper said:
I would send the carb. Out to a good shop for a rebuild and not let local mechanics touch it other than to take it off and put it back on.
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Immediately send a carb out because an engine was running rough during one taxi out? That's likely a good way to throw away a lot of money.
 
There's no primer on a 162, is there? An unlocked primer will do this.

Could be a stuck carb float. Sure sounds like way too much fuel.
 
In another life I worked at a flight school. Spent more time cleaning fouled plugs than necessary because both the students and instructors thought the mixture control was nothing more than an on/off switch. :mad2::mad2:
 
One thing that hasn't been mentioned is a sticky valve. May be intermittent as the engine gets warm and clearances open up. If it is a sticky valve, it will only get worse until it becomes a stuck valve.
 
Witmo said:
One thing that hasn't been mentioned is a sticky valve. May be intermittent as the engine gets warm and clearances open up. If it is a sticky valve, it will only get worse until it becomes a stuck valve.
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That there, too. Common enough with Continentals. Morning sickness.

Dan
 
Pull the plugs and inspect and do a compression while you're at it.

Check the carb and it's airbox for proper operation. Check mixture cable for proper operation.

Lean the snot out of it right after start up. You should be leaning so hard for taxi that it will puke and die if you shove the throttle in too fast. You cannot hurt these engines by leaning on the ground.
 
Dan Thomas said:
That there, too. Common enough with Continentals. Morning sickness.

Dan
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Dropping a cylinder will have the shakes really bad, the OP did not describe those symptoms. 0-200 seldome have stuck valves, they simply wear out the guides and loose compression. and have high oil consumption.
 
45 minutes elapsed between the previous flight and my first start, so the engine was still hot.

It was discovered that a carb heat linkage had departed the airframe. I suspect there will be more to this story.

What is the difference between running rough and having the shakes?
 
So I know I will probably upset some purists here. I fly a LSA and of course the 162 is a LSA. I get the desire to fly with a "real" airplane engine. I will say however that probably 90% of LSA's fly with Rotax engines, as does mine. I a am based at an airport at 6800 ft with DA regularly at 10K in the summer. I also fly my plane all winter. The Rotax has no pilot adjustable mixture and is very hard to get into a carb icing situation. The engine auto-adjusts mixture the whole way up to 10K feet and in reality well above that. I am just throwing out there that there are engine alternatives. I get that Cessna wanted to have an engine that many A&P's would just know how to service. That said, there are plenty of Rotax repair sites around the States.

Carl
 
GeorgeC said:
It was discovered that a carb heat linkage had departed the airframe. I suspect there will be more to this story.
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Yeah, there's got to be more. Just losing the linkage wouldn't do that. The carb heat might be on or off or floating somewhere between on and off, but shaking and refusing to restart wouldn't be part of the issue. I suspect that the carb heat valve came loose and was blocking the carb intake, maybe. Bad to have happen in flight. It probaby fell out of the way after you tried to restart, and then ran fine for the mechanic until you tried to take off and it got sucked into the intake again. Did it show a normal RPM drop with application of carb heat before you tried to depart?


Dan
 
Tom-D said:
Dropping a cylinder will have the shakes really bad, the OP did not describe those symptoms. 0-200 seldome have stuck valves, they simply wear out the guides and loose compression. and have high oil consumption.
Click to expand...

I will raise the BS flag on this one. O-200s are extremely prone to stick valves. The lead in avgas and or the carbon from too rich operation loves to collect in the valve guides and cause them to stick. Every C-150 owner is intimately familiar with the rope trick and reaming out valve guides.
 
Everyone with a carb and a fifty year old plane should check the air valve and it's rod that seats in bushings on both sides. This is an easy thing for an A&P to miss.

Mine was so bad on one side it had worn the rod in half. We replaced both bushings and rod and put new flapper material on the flapper.







The new bushings are nitrile and not needle bearing like the old ones. Much more robust for vibration. These things vibrate like your old ladies dildo. :lol:
 
Witmo said:
I will raise the BS flag on this one. O-200s are extremely prone to stick valves. The lead in avgas and or the carbon from too rich operation loves to collect in the valve guides and cause them to stick. Every C-150 owner is intimately familiar with the rope trick and reaming out valve guides.
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Did you realize this is a 0-200-D in a 162?

What does the D have that the A doesn't?
 
Tom-D said:
Did you realize this is a 0-200-D in a 162?

What does the D have that the A doesn't?
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I responded to your blanket statement that Continental O-200s are not prone to sticking valves. I have no experience with the -D but I have plenty of experience with the -A. I can't believe you have that much experience with the -D but I admit I may be mistaken. If you do have particular expertise with the -D, by all means share it with us but please specify that your comments pertain to the -D and not necessarily to all Continental engines.
 
When TCM placed the 0-200 back into production they used the technology developed by the after market cylinder manufacturers. but the engine has not been in service long enough to prove they have cured the valve problems. they are guide wear, warped valves and high oil consumption.

I have not used a reamer on a 50CI TCM cylinder in years. the ball hone has replaced the reamer. Mostly we see valve wobble causing poor compression. and there is no sense reaming an already oversized guide.
 
Skip Miller said:
The D has higher compression and requires 100LL.

-Skip
Click to expand...

They also have exhaust valve rotators, and silicone bronze valve guides developed by the after market cylinder manufacturers
 
Witmo said:
If you do have particular expertise with the -D, by all means share it with us but please specify that your comments pertain to the -D and not necessarily to all Continental engines.
Click to expand...

I have been dealing with the 0-200 for a while now, the D using the same technology as the after market cylinders is no different than any 0-200 with new cylinders in respect to the valves problems.

I have two friends that have the new carbon cubs with the D installed, both are still on factory warrantee, but they have had no problems (they are new). time will tell so we wait to see.
 
I agree that this sounds like the most likely explanation given the data so far.

Dan Thomas said:
I suspect that the carb heat valve came loose and was blocking the carb intake, maybe. Bad to have happen in flight. It probaby fell out of the way after you tried to restart, and then ran fine for the mechanic until you tried to take off and it got sucked into the intake again.
Dan
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GeorgeC said:
I agree that this sounds like the most likely explanation given the data so far.
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Since you never applied carb heat, carb ice has not been eliminated as the possible problem. I have experience with the O200D and that carb will ice right up during taxi under the right conditions.
 
Wouldn't the ice have melted in the 45 minutes between the last flight and when it ran rough the first time I started it?
 
GeorgeC said:
Wouldn't the ice have melted in the 45 minutes between the last flight and when it ran rough the first time I started it?
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Yep, missed that in your story, but the rest ( subsequently starts and runs fine, taxi, then rough again) sounds exactly like carb ice. But since you never used the carb heat, impossible to know.

Possible the initial start was rough due to water ingestion?
 
Last edited:
GeorgeC said:
Went to fly the 162 today. I was the third renter of the day. OAT about 80F, dewpoint about 65F.
That is a high temp to get carb icing. (but maybe)
Dipstick read low, added a quart, then it read 4.5, good to go. Topped off the gas and preflighted as usual.

Started up and engine ran very rough and would only hold about 600rpm, and something smelled unusual. Strike one; shut down. Tried to start again but was unable. Strike two. Decided it was time to talk to the FBO. Guy came out and must have said a blessing, because it started right up and ran great. Did a quick mag check at 1000rpm, seemed ok on either. Leaned for taxi, radio check, and off to the runup area I go.

Push in the throttle for the runup

Did you richen the mixture?

and we're back to rough running. I called it quits at that point and could only limp it about halfway back to the tiedown. FBO guys claimed to see wispy white smoke and asked me to shut down. I pull to ICO, engine surges and runs great for a few moments and then quits.

That tells me it was way too rich. a big rise like that is a sure sign there was way to much fuel in the intake system.


I'm sure glad that it failed on the ground. I'm very interested to learn the root cause.
Click to expand...

You are either flooding the engine on start, or and more probably, having a carb float valve sticking open causing the flooding.
These symptoms were the cause the AD on the MA3 floats years ago.
 
vintage cessna said:
Yep, missed that in your story, but the rest ( subsequently starts and runs fine, taxi, then rough again) sounds exactly like carb ice. But since you never used the carb heat, impossible to know.

Possible the initial start was rough due to water ingestion?
Click to expand...

He is getting a big rise inRPM at shut down, that is a sign of way too much fuel in the intake system, Carb ice there would be no fuel. and a quick drop off when the mixture is pulled to Idle Cut Off. (ICO)
 
Called the FBO for a mx update, apparently the mixture control was horked.
 
GeorgeC said:
Called the FBO for a mx update, apparently the mixture control was horked.
Click to expand...

Define "horked." Was the mixture control valve inside the carb coming loose?

Dan
 
"Computer geek slang for programming code or software that is broken, f-ked up, corrupted. Dude, your code totally HORKED the build today. " source: Urban Dictionary.
 
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