Abstract: The combination of (1) long term storage stability, (2) a relative short cure time at temperatures below about 150.degree. C. and (3) cohesive bonding of the cured elastomer to a variety of substrates is achieved in a one-part organosiloxane composition that cures by a platinum-catalyzed hydrosilylation when the composition includes an acetylenic alcohol containing at least eight carbon atoms as the catalyst inhibitor and, as the adhesion promoter, an alkoxysilane containing an epoxy group and a polyorganosiloxane containing an average of at least one silicon-bonded hydroxyl group and at least one silicon-bonded vinyl radical per molecule. The concentrations of catalyst and adhesion promoter are within specified limits.