GMAN25, I never had an operating problem. Always left the gas to sit in VST tank all winter, then serviced the filter in Spring and seen it coated, always used startron prior.
This year I drained VST now and pulled filters, may have formed more if left over winter in tank.
Also, I'm a low hour user so perhaps wouldn't make it through the season w/o filter service if higher hour usage, or perhaps would be better if used more an dhave less of it (?)
The stuff covering the filter media I can wipe on my finger, not gritty at all, don't think it's organic and not dark in color.
For some reason it reminds me of antisieze compound.
It appears as white on the surface of the dark brown VST float. Easily comes off VST filter with a shot of gumout spray. I believe it stays dissolved in the fuel since no heavy buildup in bottom of VST tank. Just a very very light wisp coating all over, hardly any materiel on white scott towel appears as silver grey on scott towel. I can't think of any material lighter or a thinner coat to compare it too. The entire inside surface of the tank produced only so much to make two thumb prints on the scott towel.
A member at THT with a signature photo of an aluminum boat with many rod holders, F150 motor, I believe reported the same material and went to 2 micron racors and no more on VST filter. So we will see. The filter media has massive surface area on racors so I suspect I'll never get close to clogging it up and will monitor squeeze bulb for collapse during a few "hammertime " hole shots all season.
The 2 microns fit same head and bowl, so it's cheap and easy enough to do even though I can do VST filter and inline filter in about 1.5 hours total both motors taking my time.
The problem I have with startron is the rep over at THT who never can produce an independant expert lab report on the stuff and talks mostly magic. So that's why I stopped and went blue stabil, figured I'd see if startron was the culprit.
If the VSTs this year stay clean, then it's happening before the motor, in the fuel tank, or pumped in from the depot and startron nor blue stabil effects its creation in my opinion.
If I wanted to spend a grand or two, I can have the material on VST filter analyzed professionally. The 2 micron racors are about 50 bucks for both. This is like a research poroject to me, will eventually figure it out myself with no help from Yamaha who has all the resources in the world to reach out to for pennies to them.