REFLECTOR: Update on N173VS static RPM

[geoff.gerhardt at gmail.com]

Jeff,

The engine shrouds are off, so the CAT pipe that would normally connect the intake to the cooling shroud is off and the servo air intake is wide open (i.e. I can see the throttle butterfly valve.

Geoff
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-----Original Message-----
From: Jeff Barnes <jcbarnes411 at sbcglobal.net>
Date: Thu, 23 Feb 2012 05:50:14 
To: <geoff.gerhardt at gmail.com>; Velocity Aircraft Owners and Builders list<reflector at tvbf.org>
Subject: Re: REFLECTOR: Update on N173VS static RPM

anything blocking your air intake ?

--- On Thu, 2/23/12, Geoff Gerhardt <geoff.gerhardt at gmail.com> wrote:


From: Geoff Gerhardt <geoff.gerhardt at gmail.com>
Subject: REFLECTOR: Update on N173VS static RPM
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Date: Thursday, February 23, 2012, 6:37 AM


As I've described, I recently started up my engine for the first time.  After sorting out some minor issues with the EI, when I tried to go to full power, I was only getting ~1900RPM static.  Also, I could only reach this power when I pulled the mixture lever way back - the engine sputtered when both the throttle and mixture were all the way in.


On Tuesday night, I discovered that one of my fuel injector lines was leaking at the connection to the injector (bad solder joint).  I repaired this and tried it again last night.  But, before I did, I pulled all the injectors out, turned the fuel pump on and observed their spray.  I measured their volume output over a 10s period and they were all approximately equal.  So, I started it up hoping all problems were solved, but it behaved exactly the same.  This time, though, I was a bit more observant of some of the engine data.  


First thing I noticed was that the Dynon Skyview indicated it was running very rich.  I forget exactly what the number was, but it was something like 30% ROP.  By pulling the mixture back at full throttle I could maximize power and the Dynon did show the mixture going from very rich to perfect/slightly lean (I forget exactly what mixture full power was reached).  But, my static RPM was still only ~1850-1900 RPM.  It was neat to see the EGT's bounce around very quickly to these mixture adjustments, tho.


The second thing I noticed was the CHT's - #3 was running significantly colder and #2 hotter than ~#1/4.  Here's a snapshot of the temps at one point from 1:341, 2:409, 3:290, 4:381.  Generally, 1/4 tracked pretty closely, but #2 got pretty hot and #3 was always at least 50deg colder than 1/4.


Just an update on the history on the engine - it was a 500hr SMOH engine that I bought from another Velocity owner who was parting out his plane.  He's an A&P who had bought the engine, pulled off the jugs, inspected the crank, replaced the rings and had it running on his velo and taxing around.  He ensures it was running well and I'm taking his word on this.  Since then, the engine's been mostly sitting in my shop or hanging on my plane pickled.  This is the first startup since I've rec'd it.


So, I'm going to check the plugs next.  Anyone else have any other suggestions?


Thanks.


Geoff


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