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10-15-2010, 02:45 PM
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Join Date: Apr 2007
Location: Memphis
Posts: 159
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IO-360 Strange Start Problem
IO-360, high comp pistons, starts normally, then fumbles, runs rough, and #2 EGT is abnormally low; condition doesn't smooth out. Engine shutdown, wait a couple minutes and restart; and restart cures the problem - no further problems. Plugs have been cleaned (look good) and the fuel line to #2 has been removed, blown out clean --- same problem persists. Mystifying!
Any ideas?
Barney, in Memphis
RV-4 flying
RV-3 flying
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10-15-2010, 03:41 PM
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Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,686
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I'd be looking for a stuck valve.
__________________
Walt Aronow, DFW, TX (52F)
EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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10-15-2010, 04:11 PM
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Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,218
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Potential induction leak. Something may be cracked and have a gap when it is cold, then the assembly heats up, grows due to the heat, and seals the gap.
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Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
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10-15-2010, 08:00 PM
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Join Date: Apr 2007
Location: Memphis
Posts: 159
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Walt,
Thanks for the heads up. I should have thought of s sticking valve myself. After reading the Lycoming Flyer, Key Operations -1 at: http://www.lycoming.com/support/tips...Operations.pdf I am even more suspicious of a sticking valve. I will so advise the owner of the aircraft of your advice.
Thanks,
Barney, in Memphis
RV-4 flying
RV-3 flying
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10-24-2010, 02:54 PM
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Join Date: Apr 2007
Location: Memphis
Posts: 159
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Stuck Exhaust Valve = Culprit
Engine has 4 into 1 exhaust: We pulled the prop through while listening with our best ear at the exhaust pipe. Three cylinders exhausted with a BIG POOF, and the culprit just hissssssed!
Barney, in Memphis
RV-3 flying
RV-4 flying
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10-24-2010, 03:07 PM
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Senior Curmudgeon
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
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Rope trick time.......
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Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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10-24-2010, 07:29 PM
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Join Date: Apr 2005
Location: St Lucie County, FL
Posts: 353
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Sounds like a stuck valve.
Whats "the Rope Trick" Mike?
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Regards
Luis  --------------------------- RV-10---------------------------  Empennage. Complete Minus fiberglass and attach section. FOR SALE
Build Log N925LC (Reserved) YouTube
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10-24-2010, 07:56 PM
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Join Date: Jul 2008
Location: Fayetteville, GA
Posts: 164
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Morning Sickness
The Dec 2010 online issue of Kitplanes has a very good article explaining the problem and how to fix it.
Title of article > Morning sickness: It?s about sticking valves.
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Tommy Turner
Fayetteville GA
RV-4 sold
RV-6 sold
RV-8 Flying
RV-14A building
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10-24-2010, 08:32 PM
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Join Date: Aug 2007
Location: Wichita Falls, TX
Posts: 2,182
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Textbook symptoms of a stuck exhaust valve.
Since it's a high compression engine, I'd advise borescoping it to see if the exhaust valve isn't burned. The rope trick, or even "staking" the valve with the rocker cover removed may only temporarily postpone the inevitable need to pull the cylinder off and send it to a cylinder shop for a proper fix.
__________________
Neal Howard
Airplaneless once again...
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11-01-2010, 02:11 PM
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Join Date: Apr 2007
Location: Memphis
Posts: 159
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Problem Fixed - Back in the Air
The problem was a sticking exhaust valve on #2. Valve was dropped into the cylinder, dragged out a the lower spark plug hole, and the stem was cleaned. Valve guide was reamed, and everything was reassembled - ground run & flight test, A-OK. The other three exhaust valves will be checked and the guides reamed (if necessary-sticking at all) at the next oil change.
Link to some helpful valve poop:
Everything You Ever Wanted to Know About Lycoming Valve Failures
http://egaa.home.mindspring.com/valves.html
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