Abstract: A tool for installing a flexible impeller within a water pump includes a sleeve having a diameter smaller than an initial diameter of an impeller in a relaxed state, a support extending about an end of the sleeve, and a translation assembly engaged with the support and configured for translating a pushing surface of the translation assembly. In operation, an impeller is contracted into a constrained state and placed in the sleeve, the sleeve is then positioned proximal or in engagement with an opening of the water pump, and the translation assembly is translated such that the pushing surface pushes the impeller into the engine assembly as the translation assembly is translated.