Today's Message Index:
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1. 05:46 AM - Re: Trouble Shooting N912RV (David Weaver)
2. 08:48 AM - Re: Trouble Shooting N912RV (Orv/Lorraine Krohn)
3. 01:43 PM - Re: Trouble Shooting N912RV (Bob Heiser)
Message 1
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| Subject: | Re: Trouble Shooting N912RV |
It would seem that the only way a Facett check valve ball could block fuel
flow would involve a large enough foreign debris to jam a check valve ball
-in the seated position.- Prior to the accident, were you seeing any si
gns of debris collecting in the firewall gas collator... like fuel tank coa
ting etc?- I am going to install a check valve in parallel with the Facet
t pump on my XP.- I am not too keen on the idea of installing fuel filter
s on the output of all three fuel tanks.- I inspect the ACS gas collator
on a regular basis to determine the health of my fuel tanks.- Thanks for
sharing information regarding your unfortunate accident.
Dave Weaver
--- On Tue, 5/22/12, Bob Heiser <w7ikt@fly-web.us> wrote:
From: Bob Heiser <w7ikt@fly-web.us>
Subject: Re: Pulsar-List: Trouble Shooting N912RV
God Bless
Bob Heiser W7IKT
On 5/22/2012 9:42 AM, Bernard Wilder wrote:
Bob,
-
When you first took the fuel system apart you said that you could not blow
back through the electric fuel pump.- You said there was a check valve. L
ater you said that you could blow through it in both directions.Doesn't sou
nd consistent. -Is it possible that there is an intermitent fault with th
e check valve in the electric fuel pump ? ? ? ?
You are right it is a puzzle as to why I could blow thru the 12v fuel pump
both ways after removing it.- Best guess it was from the rough handling r
emoving the pump.- Actually there are 2 check valves in the pump, one fix
ed and one on the shuttle that moves the fuel.- I have the pump back from
the NTSB after they took it apart.- I have inspected it and run it and d
o not see how it would block the fuel flow.- Yes I have run it in differe
nt positions.
If you still have it, shake it up, blow in both directions, abuse it to see
if you can get it to behave differently.I have tried.
-
Question: Did you have a bleed back line to the fuel cells eminating from b
etween the engine fuel pump and the carbs ? ? ? NO.
Before I put mine in I- would occasionally have trouble starting a hot en
gine and once had the engine stop because vapor lock had prevented fuel flo
w. (( I was still on the ground.))
-
Bernie Wilder-
-
-
Message 2
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| Subject: | Trouble Shooting N912RV |
Friend Terry - Thanks for forwarding the link. Very interesting! Orv Krohn
_____
From: owner-pulsar-list-server@matronics.com
[mailto:owner-pulsar-list-server@matronics.com] On Behalf Of Terry Armstrong
Sent: Thursday, May 17, 2012 1:12 PM
Subject: RE: Pulsar-List: Trouble Shooting N912RV
Bob, and All,
For a period of time, I had problems with a rough running engine (912UL)
after a warm start; whereas it always ran fine after a cold start. I had
essentially attributed the problem to vapor lock of some kind, although I
could never find the cause. A few years ago, with the help of fellow
builder, we finally resolved the issue as a corroded spring within the
carburetor.
The carburetors have some very small internal passageways that are easy to
clog and will absolutely cause problems for smooth engine operation. The
corroding spring was shedding debris into the passageways, which was causing
my particular problem. I never had an engine failure, but it definitely ran
very rough after a warm start. I suspect ethanol in the fuel was leading to
the corrosion. The corrosion didn't look like much during the original
discovery, but the impact was not trivial. Incidentally, ensuring those
carburetor passages remain clean seemed to nearly eliminate any RPM drop
between "mags" (circuits) on the check.
I had sent an email to the group detailing my situation along with spring
failures on the exhaust, but I think the email was rejected from the old
server since I had pictures to explain the problem. I've had a few other
emails fail to go through, not realizing at the time that photos were an
issue. Ultimately, I posted the information on my website. If you think
the problem could be similar, I've got a repeat of the description and
picture of the exact part at the bottom of the page. To see, click on the
following link and then "Ongoing Pulsar work":
http://terryarmstrong.com/aviation/index.html
Terry
N279TA
PS- Orv, sorry to hear you are saying goodbye to your Pulsar. I enjoyed my
previous opportunity to fly into Roswell and our visit!
_____
From: owner-pulsar-list-server@matronics.com
[mailto:owner-pulsar-list-server@matronics.com] On Behalf Of Bob Heiser
Sent: Thursday, May 17, 2012 9:14 AM
Subject: Pulsar-List: Trouble Shooting N912RV
Trouble Shooting N912RV
Group,
Looking for your experiences or ideas as to why the Rotax 912uls in my
Pulsar failed on takeoff.
Event Description:
I added fuel to N912RV's right tank to bring the total fuel in the tank to
about 6 gallons. I ran the 12v electric fuel pump for about 20 seconds
before starting the engine. I taxied to the runway (about 2 minutes)
checked the mag's at 4000 rpm and left the engine running at 4000 rpm to
bring the oil temperature up to 120 degrees (another 2 minutes). I took off
and climbed to about 50' and the engine ran rough for 3 or 4 seconds then
died completely. Fuel selector was on the right tank and the 12v electric
fuel pump was off. Also the temperature and dew point eliminate the
possibility of carb ice.
Trouble Shooting
With permission from the NTSB and the help of my son and I trouble shot the
loss of power. Note: The N912RV has since been picked up by the insurance
company.
* Mechanical Fuel Pump was removed from engine, put in vice and
pumped fuel from jar A to jar B.
* The 6 gallons of fuel in the Right Tank was lost due to crash
damage. However we removed the quick drain and were able to catch about 1
OZ of fuel, no water in the fuel. Also the lawn mower has been operating
on the same gas both before the accident and after.
* We opened up the right tank above the fuel pickup and found no
debris or obstructions by the fuel pickup elbow. The tank coating was not
pealing of flaking off.
* A clear glass fuel filter above the engine near the mechanical fuel
pump was empty of fuel after the accident. We were able to blow thru the
fuel filter in both directions and the filter was clean and contined no
debris. Also the mechanical fuel pump when removed from the engine had
little fuel also indicating a fuel starvation problem.
* We pulled the engine thru 4 compression strokes after the accident.
* All the fuel lines removed looked in great shape.
* We removed the wings to get access to the fuel selector and 12v.
Fuel pump.
* The fuel selector was removed tested and operated normally.
* We were unable to blow from the fuel filter back thru the 12v fuel
pump and fuel selector into the right tank. Thought we had found a problem,
we later found out there is a check valve in the 12v fuel pump. However
after removing the 12v fuel pump (it got bumped around during removal) we
were able to blow thru it in either direction, check valve was not working.
I sent the 12v fuel pump to the NTSB and they tested the pump and it pumped
normally and the check valve was working normally.
Note the Facet 12v fuel pump was supplied in the Aero Designs Kit. There is
no part number on the fuel pump, only a UL number, 574A, US patent numbers
and the voltage 12v. The instillation instructions describe it as a "Solid
State Electronic Fuel Pump". It is turned on for 15 seconds prior to engine
start. There were early reports of the electric pump and mechanical pump
both on flooding the carburetors, therefore I used 12v electric pump only
before starting and emergencies.
--
God Bless
Bob Heiser W7IKT
http://www.matronics.com/Navigator?Pulsar-List
http://forums.matronics.com
Message 3
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| Subject: | Re: Trouble Shooting N912RV |
Thanks for the information. The 4 minutes is the same time I had power
on before the engine faltered then quit.
*God Bless
Bob Heiser W7IKT*
On 5/23/2012 12:50 AM, Keith Palmer wrote:
> On Sunday I went up in a plane Cech factory built - with a 912S and
> had mentioned your problem to the owner so, he put the electic pump on
> for 15 seconds - turned it off - turned the fuel off at the selector -
> started, the oil temp came up in about 4 minutes then soon after the
> RPM started to die, turned fuel on - electic pump on - and we were
> away again, to the holding point for take off ??
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