TOPIC:

Lately my '80 has been starting immediately but has been taking several minutes to pick up all 6. Otherwise, running awesome ! However; Yesterday I got out on the Hwy for about a 250k spin. 85% Hwy/Freeway - posted 100KPH to 110KPH. Ran it up 5000RPM (No admiision of guilt !) for the return half. Ran relatively great, but "something wasn't right". Pulled the carbs today and mounted then in my vise. Took out the three bowl-drains and using a "really neat Tool I've got" , with the included large syringe, flushed all 6 systems 2X. Caught the discharge from the bowls:sick: in a filter. Photo shows what was in 3 of the 6 fuel-air circuits.

Non metallic, solid to the touch. If rubbed it smeared:sick: . That's a 1/16" drill.
Carbs back on, filled bowls, some choke and strait into an even idle. All good.
Didn't go C.S.I. on the debris. Don't know what it is or what part of the circuits it came from, but it's out now. It was seriously F&^%g things up !
Doesn't take much !

I'd like to go "CSI" on it. if it happened once it could happen again unless you get to the bottom of it. Good that you recognized a problem and went after it before it left you on the side of the road in Kicking Horse Pass.
Used the good ol' "Scotch Flushing Tool" with Laquer thinner I would imagine. So it's something that got in the fuel system after the fuel filter and looks like each piece is a pigtail like maybe shaved rubber or plasic and didn't disolve in gasoline since it got stuck in the idle cicuit and wouldn't self clear but will smear on the filter paper after exposure to laquer thinner. Sure sounds like it must be rubber based.
Now if I remember correctly, you have dual stainless steel braided fuel lines running to banjo fittings on the fuel supply capillaries. I'm wondering if the core of the braided lines is acting up with the ethanol in the fuel.
The other thought is that each of those pieces look about the same size, almost like a piece of rubber got cookie cut and then when the laquer thinner got to the pieces, they rolled up into pigtails? Something that could happen if a rubber line got push/twisted up on to a brass barbed fitting that was a hair too big for the tubing and the end of the barb was sharp. (thinking out loud)
Would have loved to have access to the oil analysis kit I used back in the Nuke Plant. It had a 100 power microscope we used to use to identify "debris" found in the oil samples. You wouldn't believe the S..T we could identify.

Yup, Yes, and probably with a maybe thrown in for good measure! All good deductions. The fuel lines inner liner is (White) Teflon so I'll rule out this. Compatibility with gas is listed as good to excellent. I do however have two short pieces of standard black fuel-line . One from fuel-valve nipple to fuel filter and a shorter piece to my fuel line Tee which then delivers to the outside of the left and right carbs. respectively (good memory KB !) If it is black fuel line then its got to be from the down stream piece to the Tee. Fuel filter is 2yrs year old but I have a spare and will put it on just to eliminate one part of the equation and I'll inspect the two pieces of black line at that time. I have the tank off frequently so it's probable that the end of the fuel valve nipple has a sharp edge and it's scraped off some of the material. The catch is: the fuel filter should catch it. All the more reason to change the filter ! I have on occasion reversed flushed the filter just as a maintenance procedure and now must wonder if when blowing it out with air ( carefully I believed) , I've rupture the filter membrane?

EDIT/ADDITIONAL INFO: Kawboy got the better of me. I went "C.S.I." on my suspect fuel filter when I was able to get my hands on a microscope. Opened it up (The filter - not the microscope!) and removed the mesh. Several things immediately came to light. 1st: The amount of CRAP in the filter! 2nd: The type of CRAP, 3rd: Where the CRAP was located in the filter and 4th: The source of the CRAP.
Seems I have to do the photos over two separate posts so here is the first of them:
(and I'm going back to using my CANON for future photos, cuz my cell phone SUCKS !)

Pt 2 follows:

PT 2:


1/2" to 1" very fine strands that look like "Pet Fur". Organic looking "stuff" some of which seemed similar to insect bits and pieces and saw some clear images of what I can only refer to as "crystalline" in nature. Lots of "fuzz", in general.
Now the C.S.I. part of this.
1) The filter mesh was intact 2) The CRAP was located at the open-end of the mesh - typically this is the "delivery-end" of this filter design. 3) I then have a somewhat embarrassing epiphany! The filter was installed backwards ! This particular filter is about 2+ years old and was removed last year at which time I flushed it out with Lqr thinner and blew it out with compressed air. I inadvertently installed it reversed. So for the first year+ it filtered as it should but installing it backwards now allowed the CRAP to be free to go to the carbs. Given the "Fuzzy" nature of the CRAP, for the most part it remained "stuck" to the mesh but obviously some of it did not.
Now the question is: What is it and how did it get there? Here's my theory: It's the only thing I can think of that makes sense, but if someone else has an idea, by all means.....
I've always grabbed a Paper-towel from the dispenser and use it to catch fuel-dribbles before and after filling. I sometimes wipe the end of the nozzle before filling. Gas station paper towels are probable the cheapest you'll find anywhere. The fibers are of all lengths and sizes. Where I've fuelled for the past 15 years, it's an old style towel holder that with it's simple lid is otherwise open to the air and what ever is floating in it. In this heavy agricultural area that means an unbelievable amount of dirt Cotton-wood seed, etc. and LOTS of bugs ! I doubt that the inside of the dispenser has ever been cleaned, so every times a towel is pulled out from the bottom.....You can see where I'm going with this.
I've installed a new filter and with this type: FLANGED END is the OUTLET - ALWAYS - (make note to self and not going to waste the time trying to clean them !) With the tank currently empty, I'll "swish-out" the remaining fuel and CRAP. The filter will deal with whatever's left and I'll I change filters once a year as I used to do.
Some time ago I purchased a set of carbs to rebuild and was surprised to find insect pupae casings blocking multiple Air-Mixing ports. Given this, the current issue and theory isn't that surprising.
Live and learn !

You're a good man Scotch. Not everybody would fess up and your thinking on where the debris came from is a lesson learned and shared and for that I thank you.
Now aren't you glad you went "CSI" ( Oh and for those that may not understand the term it relates to a TV show called Crime Scene Investigation)

Thanks KB ! You unwittingly put the challenge back to me. It was a humbling experience but because this topic addresses several issues and concerns it was only logical I pass the info on to others, albeit with a bit of a red-face:blush: .
Goes to prove - " You can't take anything for granted !"
C.S.I. - Continually Searching for Information

With respect to this specific fuel-filter" WIX # 33027 - I prefer this type for several reasons: 1) Small - fits almost anywhere. 2) Plenty of flow. More then adequate for the 1300's requirements. 3) Relatively inexpensive and readily available, 4) Filter comes with 2 spring-clamps, and 5) Very easy to open-up for an inspection of what's been filtered. Simply grind off the rolled edge.
The solid end of the filter is at the INLET. This conical shape diverts fuel around the entire filtering screen. The fuel flows from the outside of the screen - leaving debris trapped on the outside of the screen - to the inside of the filter and then out through the "flanged-end".
I use these spring clamps because I find them much easy to re & re with a pair needle-nose plier as opposed to using a 1/4" socket/ratchet or nut-driver and they do not cut into the fuel-line as a small worm-clamp can.