I wish I was there to walk you through it. After reading your process, It sounds like youve done most everything right. After reviewing your post, here is some more info.
First off, you should notice that the weave on the original filler is much denser than the fluval. Secondly, the cotton batting that is wrapped around the center tube is there for a reason. It sucks the surrounding juice from the filler by way of capillary action and feeds it to the coil. When you talk about burnt filler of the original filler in the carto, I'll bet that the tip of the cotton batting was what was burnt. There probably was some carbonizing of the polyfill at the bottom but the polyfill itself was not burnt. What this should tell you is that the cotton batting is actually touching the coil when in proper operation.
To trouble shoot your current situation I would venture to say that because you didn't re-install the cotton batting the juice was sliding down between the centertube and the fluval and leaking out the bottom and flooding your coil.
When you reinstall the fluval AND the cotton batting make sure that a small portion of the cotton batting is protruding out the bottom end of the filler wrap so that when the whole assembly is slid back into the carto, the cotton batting will make contact with the coil. I would say slightly less than 1/16th of an inch of batting should protrude from the bottom of the wrapped filler when you are ready to re-insert. You also must make sure that the cotton batting is wrapped tight around the straw so it will be a snug wrap around the centertube oterwise the juice will channel down between the centertube and the cotton batting and leak out the bottom. The best way I've found to do this is to first insure that your straw will fit snugly over the centertube on the carto you want to use, then remove the straw and place a couple drops of juice on the center of the straw and start your wrap of the cotton batting around the straw. Just roll the whole straw and cotton batting between both thumbs and forefingers and you will get a nice tight wrap. I usually place another drop of juice on the tightly wrapped cotton batting and this tends to stick it in place.
Now roll the original filler or fluval in the same direction as the cotton batting using your thumbs and forefingers nice and tight. Place the straw over the center tube and slide the whole assembly into the carto body while turning the carto body in the direction the filler is rolled. Once the filler is inserted as far as it will go by hand, then use the big straw to lightly tamp it down and turning the big straw IN THE OPPOSITE DIRECTION that the filler is wrapped. This is to expand the filler evenly in the carto body so the juice will disperse evenly throughout the polyfill. Remove the small straw while holding the filler in place with the larger straw to prevent the whole filler assembly from rising up when you pull the small straw.
The filler must not have any water in it or you will get no taste at all after you refill.
I've found that rebuilt cartos never hold as much juice as the original. I've also found that the 1/3rd rule with fluval(1/3rd larger in width and length) will bring the filler pack just to the top or slightly below the top of the centertube when packed properly. I let my rebuilt and refilled gocarts sit for at least 2 hours(mostly overnight) before using them. This is to allow the filler to properly expand with the new juice and redevelop proper wicking properties.
To be honest, the detailed explaination is much harder than the actual process. I have been rebuilding these cartos since march of this year and I've had less than 5 gocarts that I've had to throw away in all that time.
Keep working on this and in the end you'll get it. With practice you'll be able to move filler in and out of these puppies with no problem. Gocarts are built like trucks and as long as you don't try to remove old dry crusty filler from an old carto and pull the centertube along with the filler, these will last forever.
Here is one more step in the process I forgot to mention.......When you've dryburned the gocart and everything is clean inside, drip three drops of juice down the inside and tailpipe it before you reinstall the cleaned filler. You might find that your first tokes are weak and tasteless because the base of the coil is still wet with water. Keep dripping on the coil untill you get full rich flavor. vapor, etc. Once all that has returned, then reinstall the filler and juice.
You keep working, I'll keep you troubleshooting and in the end I'm convinced you'll get it right and it will be like falling off a log.
Good luck and keep me posted on your progress......falures and successes.
Mohawk
PS: I see that NoMoCigars is lurking in the wings on this thread and I read another post by him as to how he found his sweet spots with the gogo. Hint..........repacking the gocarts with fluval for chopper's tanks works very very well.
