Abstract: A lawn mower is powered by a quiet external combustion engine which is based on an Ericcson cycle which has been modified for more efficient combustion and higher temperature from the regenerative heat exchanger. Air is compressed in a compressor, then regeneratively heated in a heat exchanger by combustion exhaust prior to being expanded in a heated expander to generate power. The heated expander is in intimate thermal contact with the combustion chamber wherein combustion is efficiently supported by hot expanded air from the heated expander. The lawn mower includes a starter and conventional means for control, support and locomation.