A single cylinder 1360 cc diesel engine was operated on a slurry of 15 per cent by weight solvent refined coal and jet fuel. The coal was pulverized to a nominal size of 2 micrometers. The initial investigation began with nozzle bench tests which ascertained that the slurry would flow through the injection nozzle and form acceptable spray patterns. An instrumentation system was assembled to monitor and record engine operating conditions, which included pressure-time fluctuations in the combustion chamber, fuel consumption, power output, and noise. Photo-micrographs of the injection nozzle pin and injection pump plunger are presented for wear comparison before and after slurry operation.Test results indicate that the slurry fuel provides engine power and fuel consumption levels comparable to those of diesel and jet fuels. Although wear rates appeared moderate, conventional fuel injection systems are inadequate for long-term use because the clearances in the injection pump and nozzle are too small for slurry operation.