Penelitian ini bertujuan menganalisis hasil modifikasi sistem penyaringan bahan bakar pada mesin diesel Cummins QSK23-G3 dengan kapasitas 800 KVA di PLTD Musai, Desa Daik Lingga, Kepulauan Riau. Modifikasi dilakukan dengan mengganti filter ROT (Rotary Oil Type) menggunakan Purifier yang dilengkapi Separator Disk. Pengujian dilakukan berdasarkan parameter kehandalan, efektivitas kinerja mesin, dan efisiensi biaya. Modifikasi ini menggunakan pompa motor 3 phase, dengan spesifikasi Purifier yang disesuaikan dengan tekanan dan debit standar. Kehandalan mesin diuji melalui analisis data logsheet operator, terutama terkait dengan ketidakstabilan RPM, frekuensi, dan kehilangan tegangan. Hasil penelitian menunjukkan peningkatan SFC PLTD Musai pada Juli 2022 sebesar 0,274 l/kWh, dengan masa pakai filter ROT yang lebih pendek dari standar pabrikan (250 jam operasi). Hal ini menunjukkan bahwa sistem operasi bahan bakar dan kinerja mesin terganggu, yang dapat memperpendek usia material dan mengurangi kehandalan mesin. Namun, setelah modifikasi, Purifier dengan Separator Disk terbukti meningkatkan kinerja mesin, memperpanjang usia material, dan memberikan penghematan biaya pemeliharaan hingga Rp. 1.172.936.765,-. Modifikasi ini terbukti efektif dalam meningkatkan efisiensi operasional secara keseluruhan.

This study aims to analyze the results of fuel filtration system modifications on a Cummins QSK23-G3 diesel engine with a capacity of 800 KVA at PLTD Musai, located in Desa Daik Lingga, Riau Islands. The modification involved replacing the Rotary Oil Type (ROT) filter with a Purifier equipped with a Separator Disk. The evaluation was conducted based on reliability, engine performance effectiveness, and cost efficiency parameters. The modification used a 3-phase motor pump, with the Purifier specifications tailored to the standard pressure and flow rate. The engine's reliability was tested through an analysis of operator logs, focusing on issues like RPM instability, frequency fluctuations, and voltage loss. The study found that the SFC at PLTD Musai increased by 0.274 l/kWh in July 2022,and the ROT filter’s lifespan was shorter than the manufacturer's standard of 250 operating hours. This indicated that the fuel system and engine performance were compromised,potentially reducing material lifespan and engine reliability. However, after the modification,the Purifier with the Separator Disk significantly improved engine performance, extended material lifespan, and resulted in maintenance cost savings of up to Rp. 1,172,936,765. This modification proved effective in enhancing overall operational efficiency