The emission characteristics of small industrial engines have not been as thoroughly documented as those used in vehicular applications. This paper presents emission data obtained for a variety of engines, under 120 hp, primarily used for Army field power generation. A more limited presentation concerns the effects of fuel composition on emissions. In general, the emissions from gasoline engines used in generator set applications are much higher than they would be in other uses. They are operated on the rich side to enable rapid response to load transients. Emission variability from engine to engine appears to mask out any major trends with engine size that might be observed. This variability as well as variance in test replication also masks out any changes that might be observed as a result of varying fuel composition.