Hi Brian,
From what I can see they just looked at the corrosion issues that may emerge from E-10 use, specifically to brass, steel, and aluminum. Solids they found in the fuel were actually the corroded metals. They did mention that an industry trade group had formed to develop standards around fuel additives and claims that they could clean fuel systems, but this was back in 2012 and I didn't see any other update.
Yes, additives are useless in preventing phase separation (there are a few that can or may, but they have the side effect of accelerating corrosion and oxidation--throw those away as fast as you can). That was the limited conclusion of the first article. It was NOT a conclusion that additives are not valuable.
The following all have something to do with fuels.
Nov 2008
Aug 2012
Dec 2012
July 2008
Aug 2013
I did the testing.
I'm am just finishing an up-date article that should publish in Fall 2015 that includes corrosion testing, diesel bio-cides, and long-term aging tests (3-4 years, accelerated). Over-all winner will be selected, those that were "recommended" in all phases of testing.
I was probably the most skeptical of all, expecting to find pure snake oil. Instead I found a few brands the consistently produce results. All of the testing was quantitative (based upon actual or modified ASTM methods). There were reams of data, though little of the detail makes it past the editors space limitations--to all of you data geeks, sorry.
I also found some snake oil and some that actually make things worse. The NMMA is working with OEM and additive manufacturers to come up with actual standards since 2012, but there are disagreements, to say the least.
Claims that a product can fix motor problems or dissolve varnish are beyond PS testing. My opinion, based on the testing that I have done:
- Additives are for prevention, not fixes. You cannot recombine separated fuel nor should want to. They are not for cleaning tanks. They are to prevent corrosion. They can prevent oxidation and varnish formation (the next articles explains how--the key is metal activators).
- Additives should be used every time. Adding a shock dose to solve a problem is bad.
- 1/3 are worse than nothing, 1/3 are a waste of money. and 1/3 are worth every penny.
As for ancidotal evidence, I've been using the PS "best choice" products for years and I'm thrilled. Zero fuel problems (4 engines) since I made the change, and it was problems that peaked my interest. I also added an in-line filter to my 3.5 Merc and a silica gel vent filter to the main tank. And life is good.
As for draining carbs, if you read the OEM guidance, most have changed their position on that, and ONLY recommend running dry for long term storage. It has to do with the fact that you never get it 100% dry, and what you leave will dry, leaving varnish. But that will turn into an "anchoring thread."
Personally, I use Biobor EB.