A variety of types and brands of pre-mixed small engine fuels (SEFs) were analyzed by gas chromatography-mass spectrometry (GC–MS) to determine their ignitable liquid composition. Additionally, many of these brands and fuel mixes were tested six years apart, first in 2018 and again in 2024, to determine if any formulation changes had occurred. All tested products were comprised of a range of isoparaffinic content, and most also contained at least one aromatic compound. One product marketed as a fuel treatment to fix ethanol-related issues contained 2-butoxyethanol. To determine Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) ignitable liquid detection canine (ILDC) response to the specific combination of ignitable liquids in these products, ILDC teams searched representative samples of the SEFs with no detection difficulty shown for the vast majority of these products. Reporting the ignitable liquid classification of SEFs would be dependent upon individual forensic science service provider (FSSP) protocols and the appearance of the ignitable liquid in casework data. The classification possibilities for these mixtures are discussed, including a case example of data resembling an SEF.