Analisa unjuk kerja, specific fuel consumption dan emisi gas buang mesin otto empat langkah satu silinder 150cc dengan bahan bakar gasoline bernilai oktan 98 dan campuran variasi persentase bioethanol = Effect of gasoline with octane number 98 full grade bioethanol blends on performance specific fuel consumption and exhaust gas emissions characteristics of a single cylinder 150cc si engine