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Small black particles in fuel

RV12Pilot

Member
The last two flights when I tested the fuel I saw small (very small) black particles in the fuel tester. Any thoughts? Thank you, Charlie
 
Contaminated fuel and airplanes don't go together! :D You can use a "Mr Funnel" to ensure only clean fuel gets into the tank and also help work out the source of the contamination. Possibly the contamination comes from where you buy it, or during handling. Good thing you picked it up while testing.
 
Once I was the secretary/maintenance "volunteer" for 3 busy club planes, all cessna. One had a gritty feeling in the drain. Skipping ahead, we got a small cup of sand and small gravel from that tank. It turns out when standing on the ladder and lowering the fuel nozzle to the ground (from the ladder) it scooped up a little sand each time (in the wet pipe) it touched down. Think about how high wingers do that.

It could be something similar at your location . . depending on typical traffic, tarmac conditions and if people use a cap on the nozzle. Look in your fuel tank to see if there is more in that upper compartment against the ribs. Ooh - sorry you can't do that on a 12.
 
Small Black Particles

Paul is right!! A few (10) years back I found the same in my "tester" and started to make the FBO aware of the problem. Also, no additional fuel was purchased from that FBO(home base at the time). In the mean time a Christen Eagle based a few hangars down had an engine "failure" from the same small black particles in the fuel injection system. He made it, no damage, but the Christen Eagle fuel injection system was contaminated from one end to the other.

Needless to say, never bought fuel from them again, no matter what they told me. John
 
OP has only five posts so perhaps airplane is in early flight stage. That being the case, it may take a few tanks of fuel to flush debris leftover from building process.

I'm going to get lambasted for this... the very fine screen in the gascolator will prevent small particles from entering fuel lines to the carburetors. The large volume in the gascolator, compared to the small ID fuel line, allows the flow to slow down and particulates to settle out.
 
I'm going to get lambasted for this... the very fine screen in the gascolator will prevent small particles from entering fuel lines to the carburetors. The large volume in the gascolator, compared to the small ID fuel line, allows the flow to slow down and particulates to settle out.

That's kind of the whole point of the gascolator, isn't it?
 
If you get it again, tr to filter them through a paper towl and dry them. Then alaize under a magnifying glass to assertain their texture and hardness.
It could be Pro-seal.
 
The airport that we hangar at installed a new fuel tank a couple of weeks ago. My son, who has a Cherokee 6, also gets fuel at the same airport. I’ll ask him if he’s seeing any of this.
If he doesn’t then I’ll need to explore the other suggestions for sure.

Thank you
 
OP has only five posts so perhaps airplane is in early flight stage. That being the case, it may take a few tanks of fuel to flush debris leftover from building process.
SNIP

Exactly.

New tanks need to be flushed, I don’t care how tidy you were making them. Sump as needed to get a clear sample. Next make a simple jumper from the firewall fuel line connection to five gallon cans - the jumper fuel line with a cheap, clear plastic fuel filter so you can refuse the fuel for more flushes. Repeat as needed. Remove the ship fuel filter, inspect it and clean as needed. Do this before ever sending fuel to the engine.

This process is also a good time to measure fuel flow and to calibrate your float senders.

Carl
 
Exactly.

New tanks need to be flushed, I don’t care how tidy you were making them. Sump as needed to get a clear sample. ...
Very true. I found little bits of aluminum for probably my first 30 hours or so. And I must have cleaned those tanks 100 times before bolting them to the wings. I guess in-flight agitation of the tanks and a bit of time with them full of fuel knocked loose those slivers of Al.
 
Check to see if you're getting dirt or soot from the outside of the fuel drain...

==dave==
N102FM
 
Red Flag !!

The airport that we hangar at installed a new fuel tank a couple of weeks ago. My son, who has a Cherokee 6, also gets fuel at the same airport. I’ll ask him if he’s seeing any of this.
If he doesn’t then I’ll need to explore the other suggestions for sure.

Thank you

Yikes, this happened near me, they pumped all the ground fuel into a contaminated fuel truck then back into the new ground tanks. Lots of opportunities for contamination. Sometimes, they assume and don't recheck fuel quality after processes like that.
 
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I hate to be a stick in the mud---but is this a new/recent build, or an older 12 recently purchased?
Just asking--

Tom
 
Tiny gray specks

As mentioned above, after 240 Hrs on my RV3, I see minuscule gray particles in the sump test cup. Coincidently, the sump valve seems more prone to drip briefly after closing. Time for new orings and filter inspections !
 
I hate to be a stick in the mud---but is this a new/recent build, or an older 12 recently purchased?
Just asking--

Tom

My RV-12 was built by another person in 2013. I bought it last June 2020. Have flown it 70+ hours since purchase. Only saw the particles during preflight of recent flights. For preflight I did Saturday I did not see any particles.
 
isn't there some kind of filtering between the ground tank and the nozzle of the hose filling the aircraft? i have no idea but that seems so simple?
 
Small Particles

Bob, Those little black "bits" are so small from the underground tanks
they will go through the "filter" of the tank, the aircraft gascolator just fine ( it's just a screen), the fuel pump filter, and comes out the drain of a carb (Marvel 10-3878)(180hp). They do get stuck in fuel injectors.

You can barely see them in a fuel sample, very very small. Killers!!
 
Charlie---not to raise the flame war alarm, but the other possibility is the rubber hose liners are deteriorating and the black debris is parts of the fuel hoses. Being built in 2013, it most probably has rubber for all except the 2 carb hoses from the fuel block. If the previous owner changed the hoses to teflon, per the Rotax guidelines, then pardon me for butting in.

I'd take a look at them to see if they were changed.

Tom
 
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