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  #1  
Old 11-06-2013, 04:58 PM
Veetail88's Avatar
Veetail88 Veetail88 is offline
 
Join Date: Oct 2008
Location: Hales Corners, WI
Posts: 1,016
Default I guess I just can?t trust me.

I hang my head in shame before you all to let you know that I’ve reaffirmed what I know to be true about having others go over your work.

Over the past few weeks I’ve been running a thread about some problems I’ve been having with my brand new motor. From first start it hasn’t been running right and I’ve tried a lot of things trying to solve it.

I ended up with two problems. One, the motor was running rough. But not always. It would run fine at maybe 1700 RPM, and after several seconds it would choke and shutter for a bit, then start running fine again for several seconds and repeat. The other was low pressure from the mechanical boost pump.

I explored some of the ideas that came in from the VAF brain trust. I verified the mechanical pump was indeed the high pressure model required for fuel injection. I ran the motor with the red cube bypassed; I ran the motor with the mechanical pump bypassed. I checked the fuel lines for a loose fitting or b-nut, I checked the fuel filter for debris along with all of the fuel lines FWF and found nothing. I even removed the fuel pump and tore it apart looking for something wrong in there. Still nothing.

I had plenty of fuel pressure with the boost pump on and the engine still ran rough so I assumed I had 2 separate problems. I surmised that for sure the mechanical pump was bad at least, and that I had a separate problem that still needed discovery.

Well I finally fixed it all last Sunday and the problem was me. 

When I made up and assembled the fuel lines from the fuel selector through the filter and boost pump, I torqued all the b nuts and put a dab of torque seal on them, so, when “many” others on this site suggested I might have a loose fitting, I checked every one of them…….that didn’t have torque seal on them.

So last Sunday, after unsuccessfully fiddling with things for what I’d determined was the last time, I was going to pull the fuel pump back off, send it out to be tested/overhauled and shelf my motor problems until spring. I then decided I would go through all the fittings one more time, starting at the tanks and going all the way through to the injectors but this time, I’d check even those I “knew” to be tight.

You would be surprised how well that motor ran after I found that loose nut! You know, the one with the torque seal on it? Sheesh! What a dummy.Incredibly the mechanical fuel pump is producing 20 psi at idle and more at higher speed, and the motor isn’t stumbling and choking anymore! Idling real smooth now too!

So the moral of the story is the same one that is preached here all the time, and I hope I’ve learned it well. ALWAYS have 1 or more people put a wrench or screwdriver on EVERY nut, bolt, screw, etc. on the airplane!

Hope I’ve taught me a good lesson!
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Jesse Bentley
N229Z - RV-8 - Flying - Livin' the dream!

Last edited by rv6rick : 11-06-2013 at 08:44 PM. Reason: removed expletive
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  #2  
Old 11-06-2013, 05:03 PM
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Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,841
Default

As long as we continue to wrench on airplanes we will lead ourselves down the wrong path from time to time. I've been a wrench for most of my life and I still do it now and again.

The important thing is that you went back to basics and found the problem. Laugh it off and move forward with the knowledge that you are a little smarter today than you were yesterday.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
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  #3  
Old 11-06-2013, 05:20 PM
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9GT 9GT is offline
 
Join Date: Jan 2010
Location: Southern Michigan
Posts: 2,183
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Don't fell too bad Jesse. I did something very similar. After filling the fuel tanks in the -10 for the first time doing the W/B and an exciting first engine start the same day, I shut every thing down, did a cursory search for any leaks on the ramp, and put the plane back into the hanger and headed home to pack up to leave for a week at the lake house. I remembered as we were packing that I did not shut off the Andair fuel valve and that it was worth the 40 minute diversion to go out of the way to the hanger on the way up north "just in case". To my surprise I found a very large puddle of 100LL formed under the plane and a steady drip from both wing roots. After cleaning up the fuel and airing out the hanger, I found that I failed to tighten the fuel supply lines at the fuel selector valve from both tanks,,,,and I also marked them with the torque seal!
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David C.
Howell, MI
RV-10: #41686 Under Construction
RV-9A: #90949 Under Construction
RV-10: #40637 Completed/Sold 2016
Cozy MKIV:#656 Completed/Sold 2007
"Donor Exempt" but donated through Dec. 2021
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  #4  
Old 11-06-2013, 05:27 PM
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Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 6,342
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Good examples of why I (and you) should ignore torque stripes when doing inspections.
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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: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
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  #5  
Old 11-06-2013, 05:31 PM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 2,928
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Jesse--I dont think there is anyone on here that hasnt had an 'oh oh' moment. Most of the time we catch them so they are non-issues. Thats the way we like them, BEFORE the plane is in the air and has an issue that could be bad.
Good man to admit to THIS crowd that he overlooked something. Best part is, you found the issue, learned from it, as well as alot of us here too.
I finished my 7A tail, and had several eyes on it. And before if goes on the fuse (whenever that is purchased) it will have several more eyes on it. I'm not great on airframe stuff, but am learning. We all can learn from threads like this.
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Tom Swearengen, TS Flightlines LLC, AS Flightlines
Joint Venture with Aircraft Specialty
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7A Tail Kit Completed, Fuse started-Pay as I go Plan, on hold while we develop new products for RV builders
Ridgeland, SC
www.tsflightlines.com, www.asflightlines.com

Last edited by rv6rick : 11-06-2013 at 08:45 PM. Reason: removed expletives
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  #6  
Old 11-06-2013, 05:32 PM
Gisnar Gisnar is offline
 
Join Date: Nov 2012
Location: Northern Nevada
Posts: 140
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Agreed, I have learned that no nut, bolt, fitting goes on hand tight. I always leave it off or tight, no in between.
Honey, I thought you tightened the lug nuts-- do not ask.
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  #7  
Old 11-06-2013, 07:42 PM
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Rick_A Rick_A is offline
 
Join Date: Oct 2005
Location: Jacksonville, FL
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Quote:
Originally Posted by Walt View Post
Good examples of why I (and you) should ignore torque stripes when doing inspections.
One of the things I learned early on from Walt is "you can't inspect stuff by just looking at it. You've got to put a wrench on it!"
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Flying 7A Slider;
RV-12 SOLD
Jacksonville, FL
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  #8  
Old 11-06-2013, 08:35 PM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 6,320
Default Congratulations!

Good news that you found the root cause. Don't beat yourself up, though, it does not matter how much experience one has (or does not have) this happens. Just be glad you found it and your best bud didn't come by and casually put a wrench to the offending nut and accidentally "fix" it for you without a thought!

Better news is that you are now an expert on your fuel system and can help others. Maybe ME.
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RV-7
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  #9  
Old 11-06-2013, 08:51 PM
868RM 868RM is offline
 
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Location: lena, il.
Posts: 311
Default engine

Jesse, Good to here you got it sorted out. Ron
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  #10  
Old 11-06-2013, 09:02 PM
gerrychuck gerrychuck is offline
 
Join Date: Jun 2011
Location: Moose Jaw, SK, Canada
Posts: 555
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Quote:
Originally Posted by Rick_A View Post
One of the things I learned early on from Walt is "you can't inspect stuff by just looking at it. You've got to put a wrench on it!"

I'm still learning that lesson. When I did my first annual after buying my plane (we get to do that in Canada - no repairman's certificate needed up here) I eyeballed most of the nuts and bolts. This year I hired a young mechanic to help me, and she "put a wrench" on everything. She also found 3 slightly loose nuts that I missed I'll follow her example next time!
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Moose Jaw Saskatchewan
RV6A "Second Wind" C-GERZ (born N242UL)
O-360 A1A, Sensenich FP prop

Those who think any system is foolproof greatly underestimate the ingenuity of fools
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