REFLECTOR: Update on N173VS static RPM

[Andy Millin]

Check the numbers with the engine running on each of the ignition systems
separately.  If you have a plug that isn't firing, you'll see a cylinder go
cold.

 

Do only one thing at a time.  I know you know this.

 

Andy

 

 

==========================

Andy Millin

amillin at sbcglobal.net

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Geoff Gerhardt
Sent: Thursday, February 23, 2012 7:37 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Update on N173VS static RPM

 

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

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20120223/ce6cc117/attachment.htm>