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rveighta(at)comcast.net
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 Posted: Thu Sep 17, 2009 4:28 am Post subject: Engine Hesitation - Update |
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Guys, I really appreciate the outpouring of advice I received concerning my engine "hesitation" problem. I've been
on this list since 1998 and seen some flame wars that almost consumed us, but somehow we always seem to
get our bearings and get back to providing building advice to those in need.
To recap, I have an IO-360 B4A engine in my RV8A that exhibits a "hesitation" or "stumble" after taxiing in from
a flight on warm days (doesn't happen in winter). My gut feeling from the beginning was that this had to be due
to fuel vaporization, but being unsure, I tried a number of things to correct the problem:
(1) Reset idle mixture
(2) Removed and cleaned injection nozzles in a sonic cleaner
(3) Experimented with tie wrapping insulation on the lines from the flow divider
(4) Oiled the fuel selector valve
(5) Cleaned and gapped sparkplugs
(6) Checked for air induction leak using soapy water then starter fluid
None of the above action has corrected the problem, although after celaning the injectors the stumbles seemed
to occur less often.
Yesterday, as a result of an email by Kevin Horton, I called Don Rivera (really nice guy and very knowledgable) at
Airflow Performance. I described my symptoms and right away he said the fuel in the flow divider and capillary lines
was boiling due to the lack of adequate airflow under the cowl after landing. He recommended I go to smaller
diameter nozzles which would increase the pressure and reduce the possibility of vaporization. After some
calculation, Don decided on the best size nozzle ( I believe it was .022"), and I ordered the nozzles ($40/ea).
I should have the new nozzles by tomorrow afternoon or Monday. I'll install them and let you know how this works
out. I should point out that Don does NOT guarantee the problem will be entirely gone. But he said it should
greatly improve engine smoothness. We shall see.......
Thanks again for all your help, guys!
Walt Shipley
Chuckey, TN
[quote][b]
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Larry Bowen
Joined: 09 Jan 2006
Posts: 802
Location: NC, USA
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| Posted: Thu Sep 17, 2009 8:51 am Post subject: Engine Hesitation - Update |
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Good news.
Is there an expected trade off? Otherwise why not go with the smaller
from the start?
On 9/17/09, rveighta(at)comcast.net <rveighta(at)comcast.net> wrote:
| Quote: |
Guys, I really appreciate the outpouring of advice I received concerning my
engine "hesitation" problem. I've been
on this list since 1998 and seen some flame wars that almost consumed us,
but somehow we always seem to
get our bearings and get back to providing building advice to those in need.
To recap, I have an IO-360 B4A engine in my RV8A that exhibits a
"hesitation" or "stumble" after taxiing in from
a flight on warm days (doesn't happen in winter). My gut feeling from the
beginning was that this had to be due
to fuel vaporization, but being unsure, I tried a number of things to
correct the problem:
(1) Reset idle mixture
(2) Removed and cleaned injection nozzles in a sonic cleaner
(3) Experimented with tie wrapping insulation on the lines from the flow
divider
(4) Oiled the fuel selector valve
(5) Cleaned and gapped sparkplugs
(6) Checked for air induction leak using soapy water then starter fluid
None of the above action has corrected the problem, although after celaning
the injectors the stumbles seemed
to occur less often.
Yesterday, as a result of an email by Kevin Horton, I called Don Rivera
(really nice guy and very knowledgable) at
Airflow Performance. I described my symptoms and right away he said the fuel
in the flow divider and capillary lines
was boiling due to the lack of adequate airflow under the cowl after
landing. He recommended I go to smaller
diameter nozzles which would increase the pressure and reduce the
possibility of vaporization. After some
calculation, Don decided on the best size nozzle ( I believe it was .022"),
and I ordered the nozzles ($40/ea).
I should have the new nozzles by tomorrow afternoon or Monday. I'll install
them and let you know how this works
out. I should point out that Don does NOT guarantee the problem will be
entirely gone. But he said it should
greatly improve engine smoothness. We shall see.......
Thanks again for all your help, guys!
Walt Shipley
Chuckey, TN
|
--
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
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_________________
Larry Bowen
RV-8 SOLD,
RV-7QB in progress... |
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