The H2O megamaser in IC 10SE has been observed at roughly monthly intervals using the Haystack Observatory from 1986 until 1993 as part of a monitoring program of galaxies with strong water masers. The IC 10SE maser features show strong variability in line strength, line velocity, and line width. An outburst of a single feature at -324 km s-1 with a flux density increase of 400 lasts for about 1 year. The characteristics of the features support unsaturated masering and amplification of background radio continuum.