T-Dub and Peleton: My Evo Interface did the same thing, and it took me a while to figure out how it all fit back together too. Hasn't come apart since.
I was really having a less-than-wonderful time with my Evo. I've had (and love) a T1 since it came out, but its use was becoming annoying enough (top cap holes get clogged way to easily, bowl needs to be stirred, batteries barely keep up, etc) that I wanted to check out the Evo. It came last week. No matter what I tried, I couldn't get anything more than a wispy vapor cloud out of it. It was working, but not well. After completely exhausting a freshly charged set of batteries, the bottom of the load had black flecks, top of the load had lots of good stuff left.
I thought it might be the heat core was being screwed in too far, blocking its intake holes (maybe I didn't put the interface and its switch back properly), or maybe there was too much air leakage coming up the path between the core and the insulating sleeve. But my experiments indicated that neither was the problem. I took the mouthpiece and outer insulating sleeve, held my finger on the bottom, and sucked on the mouthpiece for all I was worth. No air leaks there, maybe the red O-Ring wasn't really sealing? So I put everything together, then unscrewed the "core-insulator sleeve-mouthpiece" section, held my fingers over the four intake holes in the bottom of the core, and again sucked for all I was worth. No air leaks that way either, and removing my fingers from blocking the intake holes allowed me to draw air through the whole thing with no problems.
So I was at a loss. I was beginning to think maybe my core itself just wasn't putting out enough heat, but I was also thinking it was more likely some mistake I was making, rather than a defective core. Contrary to most reports here, my (Std 6v) Evo takes almost 30 seconds from cold to full glow, with fresh batteries, and I knew it wasn't the batteries, because they still worked fine on the T1.
Then I tried this setup:
OMG! This works so well I can't believe it. Better than the T1. I get four or five HUGE hits from every load. HUGE=Massive vapor clouds with much coughing if I'm not careful. Maybe more importantly, its use is now totally predictable and repeatable. As with the T1, there is a warmup and priming hit necessary from a cold start, then four or five massive hits, then three "normal" hits after that. The ABV is totally even from top to bottom of the load, dark brown, not green or black. I can easily tell if the lack of vapor is due to the batteries getting low or the load being spent. (Hot air = spent load, cold air = spent batteries). So I don't waste precious battery life realizing the problem is the load is played.
About the only down side is that it's really pretty easy to burn yourself on the exposed metal if you're stoned. I left the red O-Ring on to remind myself. And I don't use the insulating heat core cover at all. (I ordered a couple more which I plan on modifying by removing the top section so that the mouthpiece still connects directly to the core, rather than via the insulating sleeve, but the sleeve will still cover the exposed part of the core, maybe saving me from more finger burns).
Oh, and there is another down side. The particulate-in-the-mouth problem. There is no screen or UFO in the air path. If you have a finely ground dry load, you're gonna probably get weed on your tongue. In reasonably small quantities, it doesn't bother me at all, but I know that a lot of people have a bad reaction to it. I tried stuffing a tiny screen just above the load, but it becomes a pain in the ass to deal with, and I swear it effected the flavor. The weed I load is usually not overly dry, and I don't grind it, I crumble it with my fingers. I load the core by "scooping" the crumbled weed out of my hand directly into the top of the core, until the core is full to the top. I very lightly tamp it down with the equivalent of a pencil eraser, maybe 3 or 4mm, just enough to make room for the part of the smooth-flow to fit in without hitting the top of the load. Very lightly is key here. If I pack it down, rather than tamp it lightly, a hernia inducing draw becomes necessary; if I don't tamp it down at all, I get a fair amount of particulate in my mouth. With the kind of weed I get, and a finger crumble rather than a grind, and a very light tamp, I get essentially no particulate and a very easy draw.
I would encourage everyone who has an Evo to try bypassing the insulating sleeve, and give what I picture above a try. I still think I'm probably doing something wrong when I have things setup the normal way, but this works SO much better for me that I wanted to share it.
And I still have no idea why the "normal" way isn't working for me. I try it again every few days, and it produces miserable results every time. Going back to the method above works 100%.
I am having a bit of fun 
I've been running the 3.7v so far tonight, I think I will try the 6v now without the sleeve.
I then proceeded to "honk" on it. Nice cloud, great flavor. First thing I found is the Evo likes to be packed, I got better results when it was full and packed in just a smidgen. Very happy so far, more to come 
Happy for you Tdub! Welcome to flavor country...it's a biiiiiig country 
