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  #1  
Old 09-19-2018, 04:28 PM
TShort TShort is offline
 
Join Date: Jan 2005
Location: Indianapolis, IN (KUMP)
Posts: 806
Default Help needed troubleshooting rough running O-320

I'm hoping for some wisdom / assistance in helping a friend troubleshoot a rough running engine in his purchased RV-9.

Background: RV-9, carb'd lycoming o-320, dual mags, pretty much basic setup as per vans.

Jim bought the airplane earlier this year, it was pretty new with phase I flown off. Has about ~75 hours now. Aside from some warmer CHTs, the engine had been running fine.

Early Aug, he and a friend flew to a nearby airport for fuel. On return, (in the dark!) the engine began running rough. Runs rough at higher power, seems to smooth out if the throttle is pulled back.

I am going to link to engine data from 2 flights:

First, before any issues arose and the engine was running well (this was takeoffs and landings at our local airport):

https://savvyanalysis.com/flight/271...4-e3f9159664d2

The flight where issues arose:

https://savvyanalysis.com/flight/271...4-0a621ccead39

I am going to share the link with Jim so he can register / login and help answer any other questions. Not sure he is on VAF yet.

Thanks in advance for any thoughts / suggestions
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Thomas Short
KUMP - Indianapolis, IN
RV-10 N316JS bought / flying
RV-8 wings / fuse in progress ... still
N329TS (had it, lost it, looking for new number)
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  #2  
Old 09-19-2018, 04:32 PM
TShort TShort is offline
 
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Location: Indianapolis, IN (KUMP)
Posts: 806
Default

Here are screenshots of the above flights (clicking the savvy links in the above posts takes you to the actual data, where additional parameters can be added / compared):

Normal flight:



Rough engine:

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Thomas Short
KUMP - Indianapolis, IN
RV-10 N316JS bought / flying
RV-8 wings / fuse in progress ... still
N329TS (had it, lost it, looking for new number)
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  #3  
Old 09-20-2018, 01:44 AM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,661
Default Savvy analysis

Tell your mate Jim to dust the cobwebs out of his wallet and get Savvy Analysis to inspect the data. They are the absolute experts at this. Their opinion would undoubtedly be more valuable than any free opinions on this forum.
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Bob Barrow
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  #4  
Old 09-20-2018, 07:41 AM
krw5927 krw5927 is offline
 
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Location: Wichita, KS
Posts: 1,881
Default

Those are some seriously high CHTs.
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  #5  
Old 09-20-2018, 08:27 AM
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MarkW MarkW is offline
 
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Location: Edgewater, FL. KSFB
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As Kurt says, kinda high on the CHT's.
It would be very helpful to know at what time it started running rough.
There is a large FF drop at 25:52 with a small RPM change.
If that is where the problem started it sure looks like fuel flow.
However EGT #4 started wondering of about 23:30.
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  #6  
Old 09-20-2018, 10:14 AM
TShort TShort is offline
 
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Location: Indianapolis, IN (KUMP)
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Quote:
Originally Posted by Captain Avgas View Post
Tell your mate Jim to dust the cobwebs out of his wallet and get Savvy Analysis to inspect the data. They are the absolute experts at this. Their opinion would undoubtedly be more valuable than any free opinions on this forum.
Haha. We talked about that.

There is tons of great knowledge on this board ... I was hoping for some insight or thoughts on troubleshooting.

The front page exposure definitely helps - thanks Doug!
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Thomas Short
KUMP - Indianapolis, IN
RV-10 N316JS bought / flying
RV-8 wings / fuse in progress ... still
N329TS (had it, lost it, looking for new number)
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  #7  
Old 09-20-2018, 10:15 AM
TShort TShort is offline
 
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Location: Indianapolis, IN (KUMP)
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Agree about the CHTs
We've talked about that and are looking at the issue.
Baffles etc look good.

Anecdotally, he's been told "this is a common problem with the RV-9 in climb" - any truth to that?
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Thomas Short
KUMP - Indianapolis, IN
RV-10 N316JS bought / flying
RV-8 wings / fuse in progress ... still
N329TS (had it, lost it, looking for new number)
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  #8  
Old 09-20-2018, 10:27 AM
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Tumper Tumper is offline
 
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Location: Aubrey, TX
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Looks a lot like my EKG...
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  #9  
Old 09-20-2018, 10:33 AM
jpowell13 jpowell13 is online now
 
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Location: Baton Rouge, LA
Posts: 570
Default Loose Carb?

This may be totally off (I'm no expert) but its easy to check. Have the nuts that secure your carb loosened up? John
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  #10  
Old 09-20-2018, 10:45 AM
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Shark Shark is offline
 
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Location: Lake Elmo MN
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Quote:
Originally Posted by jpowell13 View Post
This may be totally off (I'm no expert) but its easy to check. Have the nuts that secure your carb loosened up? John
I had a similar experience, the carburetor bolts backed off that held the carb together which intern allowed the carb to split just enough to leak gas when the fuel pump was on and I'm assuming suck air when it wasn't. Anyway she ran a bit "rough" (Scary) all fixed and safety wired
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