Boat Repair Costs
Marine Generator Repair & Replacement Cost Guide
Published April 26, 2026
Researching marine repair costs, ownership expenses, and protection plan options for boat owners.
A marine generator is one of the most failure-prone systems on any boat with onboard AC, refrigeration, or live-aboard capability. When it fails, the cost of repair sits in a wide and uncomfortable range: as little as $1,500 for a service call, as much as $25,000+ for a full replacement.
Marine generator repair cost ranges
- Routine service (impeller, oil, filters, zincs): $400 – $1,200
- Cooling system repair: $1,500 – $4,500
- Starter, alternator, voltage regulator: $1,200 – $3,500
- Control board / ECU replacement: $1,800 – $4,000
- Top-end rebuild (head, valves, injectors): $4,500 – $9,000
- Full generator rebuild: $8,000 – $14,000
- New generator + installation: $12,000 – $25,000
For a broader picture of where generators fit in the overall cost of boat ownership, see our boat ownership cost guide.
Why generators fail so often
- Heat-soaked engine rooms that rarely get below 110°F under way
- Saltwater raw-water cooling corroding heat exchangers and exhaust elbows
- Low operating hours at peak loads, which causes carbon fouling
- Electrical and control-board damage from voltage spikes
Repair vs replace
If your generator is over 5,000 hours and needs a top-end rebuild plus cooling-system work in the same visit, replacement is almost always the better long-term decision. Below that threshold, targeted repair is usually the smarter call.
How extended marine warranty plans handle generators
Generators are typically covered under mid- and upper-tier marine warranty plans, including:
- Crankshaft, head, valves, and injectors
- Cooling system components
- Control boards and electrical
- Voltage regulators and alternators
Filing a generator claim follows the same process as any other covered system — see our claims process page for the full walkthrough.
What to do before something fails
- Run the genset under load for at least 1 hour every two weeks
- Replace impellers annually, not "when they fail"
- Inspect zincs every 90 days
- Get an extended warranty quote before the unit hits 1,500 hours, when premiums are lowest
Request a quote and we'll tell you exactly what coverage looks like for your specific generator make and model.