Diesel Engine Hourly Maintenance Schedule

These are suggested marine diesel engine checks and maintenance items by hour interval. Check the manufacturer's recommended maintenance schedule for added checks or variations for the exact engine.

Before every engine start

• Check oil level, color, and smell.
• Check belts for tightness and cracks.
• Check hoses for cracks or leaks.
• Check coolant level.
• Check the fuel filter bowl for water.
• Check the raw-water strainer for debris.
• Confirm the engine is in neutral.

After every start

• Check water discharge.
• Check smoke amount and color.
• Check raw-water weep holes; the source notes they should be dry after running.
• Listen for unusual noise or vibration.
• Complete a visual inspection for vibration and related issues.

50 hours or 6 months

• Check or replace the primary fuel filter.
• Check transmission fluid levels.
• Check zincs if provided.
• Clean the engine and touch up paint if needed.
• Complete a visual inspection, including exhaust system and fuel tank.
• Check the O-ring on the fuel deck fill.
• Check that the fuel vent is clear.
• Check the packing gland and valve clearances.

100 hours or 12 months

• Change oil and oil filter together.
• Change transmission fluid.
• Replace the primary fuel filter.
• Repeat the 50-hour or 6-month checks.
• Check or replace the secondary fuel filter.
• Do a full engine survey over all systems.

200 hours or 24 months

• Repeat the 50-hour or 6-month checks.
• Drain and flush coolant.
• Inspect or replace the raw-water impeller.
• Inspect or replace the air filter.
• Check engine alignment.
• Check transmission fluid.
• Inspect the exhaust elbow.

500 hours

• Replace hoses and belts.
• Rebuild or replace the raw-water pump.
• Check head torque.
• Check valve clearances.
• Check injectors.

Next step on CLR Marine

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