ALERT! - Fuel hose obstruction!

[RV7A Flyer]

Originally Posted by RV6_flyer

Maybe I am the only homebuilder that does it, but I have an assortment of these caps in my shop and any fitting that is not connected has one on it.

You're not the only one

ETA: to the OP...you mentioned poking a hinge pin into the tube to break up the obstruction. I'm not sure but that I wouldn't just toss that hose now...I don't know what the effect of scratching the inside of the tube with something sharp (like the end of a hinge pin) might be.

That might be overly cautious, but unless someone can chime in here and give some advice on how to inspect it, or that it's okay and can tolerate scratches, I'd err on the side of being extra careful with my fuel system.

[krw5927]

Originally Posted by RV7A Flyer

You're not the only one

ETA: to the OP...you mentioned poking a hinge pin into the tube to break up the obstruction. I'm not sure but that I wouldn't just toss that hose now...I don't know what the effect of scratching the inside of the tube with something sharp (like the end of a hinge pin) might be.

That might be overly cautious, but unless someone can chime in here and give some advice on how to inspect it, or that it's okay and can tolerate scratches, I'd err on the side of being extra careful with my fuel system.

I sort of had the same thought, although I have no data to say whether "scratching" the teflon liner may be a problem. Perhaps Tom From TS Flightlines can weigh in?

[newt]

Originally Posted by jcarne

I'm assuming flushing is good practice as Mel mentioned but what do you flush with?

Fuel?

It's a solvent, and it's guaranteed to not damage the fuel line.

The suggestion of dragging a fuel-soaked bit of rag (ghetto pipecleaner!) through the length of the hose is a good one too.

- mark

[BillL]

Originally Posted by Mel

Keeping hoses sealed until installation is great and I do it , but it is still no excuse not to "flush/purge" immediately prior to installation.

+1 - take a piece of foam, stuff in the end and blow through, wet with wd40 , mineral spirits do it 3 times. Then install. Ear plugs work well. Open cell foam is best to collect internal debris. This is standard QC process at hydraulic assembly plants where miles of hose gets installed weekly.

Who knows where the hose has been.

[BSwayze]

Originally Posted by RV7A Flyer

ETA: to the OP...you mentioned poking a hinge pin into the tube to break up the obstruction. I'm not sure but that I wouldn't just toss that hose now...I don't know what the effect of scratching the inside of the tube with something sharp (like the end of a hinge pin) might be.

That might be overly cautious, but unless someone can chime in here and give some advice on how to inspect it, or that it's okay and can tolerate scratches, I'd err on the side of being extra careful with my fuel system.

I appreciate this very much, Joe. The hinge pin I used had been rounded on the end and polished on my wheel, to make it easier to insert into the cowl hinges. There are no sharp edges at all, so I'm not too worried about it. Thanks for the suggestion!

[TS Flightlines]

Good catch Bruce! As far as the hinge pin is concerned, its probably just fine. I'd retest the hoses, just to make sure that the liner didnt get nicked in the process. Flush the hoses, and re-cap them until ready for install. UH----same for the filter, pump, etc, anything that has been left open.
Mud daubers, dirt, RTV, loctite, anything that could possibly create a restriction.
One of our local clients had a very small piece of something that restricted a port in the flow divider. AND all of his stuff was capped off----so definitely check things.

Tom

[Flyin'Bryan]

Guess I better go check my flop tube that has been sitting on the shelf for - well - let's just say a lot longer than I care to mention. Both ends have been wide open the whole time. This even makes me wonder about the metal fuel and vent line tubing, and other NPT fittings that have been tucked away in my plastic storage drawers along with all the rivets, etc. for a very long time. You know, the ones where I periodically find dead spiders and such in the bottom of the drawer......

I've got plenty of ear plugs laying around doing nothing, so that will change. Maybe it's time to order some caps too.

Thanks for the warning and the wake up call Bruce!

[LettersFromFlyoverCountry]

I've got a few of the threaded hose fixtures described above handing around the hangar doing nobody any good.

If anyone needs them, drop me a line. No charge.

[jrs14855]

For those who do not want to chase down the caps, a double layer of aluminum foil wrapped around the end and secured with rubber band or wire tie works well. For the shorter hoses wrap the entire hose or put it in a zip lock bag.
The cleaning brushes for the old fashioned coffee makers are probably very hard to find these days. They make an excellent cleaning brush for the -4 and larger hoses. Dish soap and lots of hot water. Stick them in the oven at around 200 degrees to get rid of any trapped water.

[TS Flightlines]

LARGE zip plastic bags, like the 2 1/2 gallon size is great for storing things like hoses, fuel pumps, filters, selector valves, etc. that have been flight ready.

Oh and the idea of sealing the fuel hoses also pertains to the brake hoses too--pitot lines, your coiled up aluminum tubing too.

Good idea that even after you remove the cap plugs use your air compressor to blow through them, just to make sure. Because, if youre like me, you may have checked them several years ago and put caps on them. Or did you? Memory gets hazy after a while. Dont guess, check it.

Tom