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Old 10-27-2014, 04:34 AM
N941WR's Avatar
N941WR N941WR is offline
Join Date: Jan 2005
Location: SC
Posts: 12,887

I'm with the others, this doesn't sound like an ignition issue. Two mags, four wires, or four plugs just don't go bad all at the same time.

That leaves the primer, induction, and exhaust.

The fuel puddle is a new clue. Remove and inspect everthing, starting with the primer.
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
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Old 10-27-2014, 06:18 AM
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RV10inOz RV10inOz is offline
Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,308

And maybe don't reinstall the primer!

David Brown

DYNON Authorised Dealer and Installer

The two best investments you can make, by any financial test, an EMS and APS!
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Old 10-27-2014, 09:56 AM
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WA85 WA85 is offline
Join Date: Apr 2010
Location: Huntsville, AL
Posts: 170

I had a similar problem years ago on an O-320. Out of the blue, I had two of the hydraulic lifters/ tappets on the same side fail due to the internal check valves getting stuck open due to blockage, preventing the valves from opening all the way. I think I had one intake and one exhaust, could have been both intake. The symptoms were two rough running / dead cylinders on the RH side. Since the both lifters were not "pumping up", the valves didn't open properly, thus it passed a compression test easily. I did everything you did until I pulled a valve cover and found the two valves were barely opening. I removed the push rod tubes / rods and attempted to remove any debris from inside the lifter by squirting solvent into the center hole and sucking the debris out with a vacuum. I then re-installed everything except the valve covers and rotated the engine over until oil pressure was indicated. I measured the valve action at the rocker arm and they worked OK after that. Whatever I did, it worked and the engine ran OK afterwards. Your issue may not be related to this at all, but it might be another idea to help you in your troubleshooting.
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Old 11-05-2014, 02:37 AM
abnranger69 abnranger69 is offline
Join Date: Oct 2010
Location: Sacramento, ca
Posts: 11
Smile ****UPDATE****

Well, winner winner, chicken dinner!

It was a primer pump issue. Had a failure in the primer pump solenoid that was allowing max fuel to be pumped into the L side cylinders, thereby "drowning" them out/over rich. Totally makes sense now.

Sure appreciate everybody's input, definitely helped me sort through things. Start simple and work from there..... learned a lot!

Thanx again!


Last edited by abnranger69 : 11-05-2014 at 02:55 AM.
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Old 11-05-2014, 05:26 AM
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turbo turbo is offline
Join Date: Jan 2007
Location: Stuart, FL /Hartford, CT/Virgin Gorda,BVI
Posts: 3,177

TURBO YES =VAF= Payed Jan2021
Ed D'Arcy
RV6-A 5,300+ hrs, R-44 1,600 hrs, Helicycle traded for 33 FFR coupe, 300 young eagles flown
Stuart, Fl / East Hampton,Ct / Virgin Gorda, BVI - villa sold.
addicted pickle ball player
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Old 11-05-2014, 06:15 AM
humptybump humptybump is offline
Join Date: Feb 2011
Location: USA
Posts: 3,181

Thanks for the update Dave. Good sleuthing!
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Old 11-05-2014, 08:49 AM
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n82rb n82rb is offline
Join Date: Jan 2007
Location: fort myers fl
Posts: 1,092

glad to hear that you found it and it was a easy fix.

bob burns
RV-4 N82RB
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Old 11-07-2014, 11:50 AM
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dave4754 dave4754 is offline
Join Date: Oct 2009
Location: Edson, Alberta, Canada
Posts: 493
Default Thanks for the info

I was looking into the primer issue as I am now into the QB fuse and doing my fuel system.

This reinforces my opinion that I think I will use the manual piston primer and keep it simple.

When I phoned Vans they asked why I needed one, of course they rarely see -20 C flying days like we do here in Canada. Nothing like a crisp cold day of flying over a white landscape eh?

Thanks again.
Dave Cobb
[color="Red"]=VAF=2019 Donation - and a bit extra for great work![/COLOR="blue"]
Empennage RV 7 - Tipper
Wings complete

Dynon installed and running
Fuse closer to completion, Canopy complete
AME reviewed and repaired O-320-Lyc installed
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Old 11-07-2014, 12:58 PM
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Walt Walt is offline
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 6,358

Better yet just go with fuel injection, no primer, no carb ice
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, 2000+ hrs, New Titan IO-370, Bendix Mags
Website:, Email:, Cell: 972-746-5154
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Old 11-08-2014, 09:50 AM
ao.frog ao.frog is offline
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default Right on!

I'm impressed: this guy was right on! Way to go Paige!

Originally Posted by PaigeHoffart View Post
This is a bit of a reach, but do you have primer lines to the left cylinders only? A stuck primer solenoid causing them to run way over rich at idle?

Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!
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