The International Cessna^® 170 Association

Somehow, a lot of trash has found it's way into my right fuel tank - it appears to be organic, as in tiny bits of leaves or insects. Even after draining almost a gallon, I was still getting debris.

So the plan is to remove the sump valve and drain and flush the tank with fresh gas. This got me to thinking - has anyone ever removed the fuel strainer assembly to check the finger screen for debris/clogging? After 54 years, this might be a good idea!

My fuel strainer bears no resemblance to the picture in the IPC - it's a straight fitting, the IPC shows a 90 degree elbow fitting. I'm assuming it's a NPT thread; if it doesn't come out with moderate force, I'll leave it in.
Plan B would be to blow some low pressure air, like 10-15 psi through the fitting to knock off any accumulated trash, then flushing the tank.

If anyone else has been down this road, I'd appreciate some input...Russ Farris

I had the similar problem several years ago. "Appears to be organic" is a good discription. Tiny flecks that would not go away. I was told by an A&P that it was caused by a type of fungus that can live in the gas. I have no idea if that is true or not, but he did say it with a straight face. I drained the tanks out the sump (I did not flush them, but that sounds like a good idea) and the problem was gone.

There are bacteria that can live in water (keep your tanks sumped), and eats diesel and jet-fuel/kerosene. The body-wastes can produce a bio-mass/matt that can be "junky" and clog filters/screens and cause corrosion. I've never heard of it in gasoline tho'.

There are commercial products which control/kill the bacteria, one of which is produced by the old "Twenty-Mule Team Borax" folks, ...called JB-Biobor. I've purchased it at Aviation Supply houses for jet fuel.

Russ, do you/have you used autogas? (Not trying to start anything, folks. Just trying to search for causes/solutions that I've found previously.)

Sure George, you're not trying to start anything Yep, pretty much autogas with an occasional fill-up of avgas.

I drained the tank today...I identified a leg and part of a wing, so the current working theory is some bug made a bull-eye hit on the fuel vent and ended up in the right tank.

Like George said, I've never heard of bacteria living in gasoline. In the mid 1970s working as a lineboy, I remember using Prist in Lears to kill the bugs.

Removing the fuel strainer was a non-event. Came out easily, and the coarse wire finger screen looked perfect. Unless you suspect a problem, I wouldn't bother removing it. Installed a new CAV-170 drain while I was at it, since the old one was seeping (autogas???)

Thanks for the input, guys...Russ Farris

Ha! Well, just to make you feel better, my right CAV-170 will be replaced before Kelowna. It's dripping AvGas.

BTW,...Prist no longer claims to fight bugs (bacteria/fungus) in the fuel. I've been anecdotally informed that the bacteriacide has been removed as an ingredient. Prist only claims anti-icing properties these days.

Also, (some of you guys are gonna love this one...) I have an "undocumented" modification to my fuel system. I discovered one day (while fooling around with an empty Alcor TCP can) that the screen/strainer at the bottom of the pickup tube in that can is EXACTLY the correct size for the gooseneck fuel vent in a 170. The screen is "hat" shaped...just like a top-hat.... so it's body fits right down into the tube with a nice friction fit, ...but the "brim" prevents it from going on down into the tube. It's made of fine-mesh stainless steel screen. No bugs larger than a molecule of air will get down there. It's been at work on my airplane now for about 4 years.
Now I once mentioned this before, and someone out there contacted me and asked me for the next screen that came out of my next can of TCP, and I told them I'd send it. The problem is: I didn't buy anymore 1 qt. cans of the stuff....I bought it in 1 gal. cans which don't have that pickup tube. (And I can't remember who I made that promise to, so I can't contact them to apologize and explain. Is it someone who's reading this now? Please contact me.)

George,

C'est moi.

But if you do find one, I'll be happy to pay for it .
chuck

Hey, don't discount the possibility of the fuel float deteriorating. I was getting little specks of matter out of my left sump, this occurrence almost hasn't happen as I don't let my left tank ( only 12 gals) get low to were the float bounces and vibrates on the tank bottom. this is my sop until I get into changing or resealing the float.