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Best Overall (Fuel Storage)
Top corrosion protection, best flammability of the group at 20 months
Purchased for: $6
Made In: USA
8 oz. Claims effectiveness in all ethanol blends. SDS notes ~95% hydrotreated light petroleum distillates + ~5% isopropylated phenol. Best corrosion protection, slightly better flammability than others at 20 months, easy generator start.
Also one of the cheapest per bottle tested.
Easiest Cold-Start on Stale Fuel
Started and ran generator without ether
Purchased for: $7
Made In: USA
8 oz. ~100% hydrotreated light petroleum distillates. Poor corrosion protection in water-contaminated E10, but excellent generator starting on stale fuel (no starting fluid).
If your fuel is already old, this performed best in the live generator run.
Runner-up (Balanced)
Decent flammability & acceptable corrosion control
Purchased for: $12
Made In: USA
8 oz. Alcohol-based (incl. ethylene glycol). Better flammability, moderate corrosion (some sludge), decent generator performance (minimal ether).
Good middle-ground performance across tests.
Bottle prices cited in the video: STA-BIL ($6/8oz), Star Tron ($7/8oz), K100 ($12/8oz), SeaFoam ($10/16oz), Marvel Mystery Oil ($14/32oz), Yamalube ($20/32oz).
Subjective visual scoring from the teardown. STA-BIL showed virtually no corrosion, K100 showed light residue, SeaFoam and Star Tron had substantial corrosion, untreated was worst.
Measured with a durometer after soaking in each treated fuel. Differences were small, STA-BIL was softest (48.5).
None of the samples remained truly ‘fresh.’ STA-BIL was the only one that began to ignite, all others rated worst case.
STA-BIL and Star Tron started without ether and ran smoothly, K100 needed a bump to start but then ran, others required more assistance and/or produced more carbon.
Follow-up from the prior headlight review: Sylvania held up best after a year of UV exposure, closely followed by Cerakote.