Diesel vs Gas Inboard Engines: Complete Comparison

For larger boats with inboard engines, the diesel vs. gasoline debate is an important decision. Each fuel type has significant advantages depending on your boating style.

Diesel Inboard Advantages

Fuel Efficiency

• 20-30% better fuel economy than equivalent gas engines
• Diesel fuel contains more energy per gallon
• Significant savings for high-hour operators

Longevity

• Diesel engines typically last 5,000-8,000+ hours
• Gas engines typically last 1,500-2,500 hours
• Diesel's slower RPM reduces wear

Safety

• Diesel fuel is less volatile than gasoline
• No explosive fumes in engine compartment
• Reduced fire risk

Torque

• More low-end torque for heavy displacement hulls
• Better for pushing through rough conditions
• Excellent for trawlers and cruisers

Gas Inboard Advantages

Initial Cost

• Gas engines cost 30-50% less than equivalent diesel
• Lower initial investment
• Makes sense for lower-use boats

Performance

• Higher RPM capability
• Better power-to-weight ratio
• Preferred for ski boats and performance applications

Maintenance

• More mechanics familiar with gas engines
• Parts often less expensive
• Simpler fuel system

Cost Comparison

Factor	Diesel	Gasoline
Engine Cost	Higher	Lower
Fuel Cost/Gallon	Similar	Similar
Fuel Economy	Better	Worse
Maintenance Cost	Higher per service	Lower per service
Lifespan	Much longer	Shorter

Best Applications

Choose Diesel For:

• Cruising boats used 200+ hours/year
• Long-range cruising yachts
• Trawlers and displacement hulls
• Commercial applications
• Liveaboard boats

Choose Gasoline For:

• Ski and wakeboard boats
• Boats used under 100 hours/year
• Performance runabouts
• Budget-conscious buyers
• Boats that will be sold within a few years

Shop Inboard Engines

Power Marine Engines carries both diesel and gasoline inboards. Browse our inboard selection or contact us for recommendations.