Black Flakes..
If you made up your own hoses, the rubber crumbles when you cut the
hose and could also abrade when you install the hose ends. If you don’t
properly wash them out before they are installed, this material could flush
through the system and plug your filters, injectors, or wind up in the tank if
you have a return system. Don’t ask me how I know.
:>)
Anybody know a good way to flush out injectors?
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Tracy Crook
Sent: Friday, February 27, 2009
10:43 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: ethanol
FWIW,
Possible source of the 'black flakes' is fuel pump impeller pieces.
When these pumps run dry their lifetime is measured in minutes. The
impellers will abrade and shed small pieces. Insure that the path from
tank to pump is down hill or at least level with the fuel and there are no
restrictive filters or other obstacles in this path. I don't even like to
see boost pumps there because there is a significant drop in pressure across
their check valves.
Tracy
On Thu, Feb 26, 2009 at 10:59 PM, Mike Wills <rv-4mike@cox.net> wrote:
Well things seem a little slow today so how about re-opening
a can of worms? We had a brief discussion a while back regarding ethanol in
fuel. Frankly at the time I didn’t know much about the subject but have
been reading a little since I'm burning auto fuel.
At the time I think it was Al G. who said so far he hasn’t
found any auto fuel with ethanol in it. If I got that wrong I apologize. So far
I haven’t found any auto fuel that DOESNT. As far as I can tell from my
reading ALL auto fuel in CA has at least 6% and most is at 10% now.
Looks like the concerns are:
2) Potential corrosion of aluminum components in the fuel
system.
3) Deterioration of rubber (and other?) components in the
fuel system.
5) Dislodging contaminants from previously used fuels.
I believe (hope?) the vapor lock issues to be a
non-problem with our EFI systems. The potential corrosion issues seem to
be overstated for ethanol, clearly a problem with methanol. All the hose in my
airplane is Earls Perform-O-Flex which according to their website is
"synthetic rubber". I assume they mean neoprene which I gather is
ethanol safe. I assume the injectors themselves are safe? I
thought Pro-Seal is also supposed to be ethanol safe. My airplane is new
so there should be no issue with dislodged contaminants.
This leaves the issue of ethanol's affinity for water. Other
than always keeping the tanks full to minimize airspace in the tank and
condensation any ideas on how to deal with this other than hoping it doesn’t
happen?
I bring this subject up because for the second time since
I've started flying I've found a little contamination during my pre-flight when
sumping the tanks. Each fuel sample has a few ground pepper sized black flakes
in it. Whatever it is it crumbles to powder between the fingers. The first
time I completely drained the tanks and pulled the fuel filters and
cleaned them. When I refilled the tanks I used a Mr. Funnel to make sure
nothing bad got added. So whatever this is, its residual junk in the tanks from
when they were built. Or its something (like ethanol) attacking the Pro Seal.
Any comments on ethanol in general or my fuel contamination
issue are welcome.