MARATHON Melting Kettles for sale in Winston Salem, High Point, Greensboro, NC area. Diesel-fired The 130, 230 and 370-gallon diesel fired compound melting kettles are trailer mounted and have electric brakes. They have a Kubota 6 hp diesel engine. They have a single 324,000 BTU diesel burners on them. Propane fired units with gas engine are also available in the 130 gallon, 230 gallon & 370 gallon kettles which come equipped with electric brakes also. Hydraulic agitation on the diesel units and mechanical agitation on the propane units. Many optional features are available.