What is a 100-hour boat engine service?

A 100-hour service is the foundational scheduled maintenance interval for most marine engines. It includes oil and filter changes, fuel filter replacement, cooling system inspection, impeller inspection, spark plug check, and a full diagnostic scan. It should be performed every 100 engine hours or annually, whichever comes first.

What's the difference between a 100-hour and 500-hour service?

Each interval builds on the previous one. A 100-hour service covers basic fluids, filters, and diagnostics. A 200-hour adds fuel system and ignition work. A 300-hour includes cooling flushes and exhaust inspection. A 500-hour is a major overhaul with complete fluid replacement, valve adjustment, injector testing, and comprehensive systems check.

Is the 20-hour service required for warranty?

Most marine engine manufacturers require a 20-hour break-in service to maintain warranty coverage on new engines. This service verifies the engine is performing correctly after its initial break-in period and typically includes an oil change, belt and hose inspection, and systems check. We document the service for your warranty records.

How do I know what service interval my engine needs?

Check your engine's hour meter — it tells you the total running hours. Match that to the closest service interval. If you're unsure, contact us and we'll check your engine hours and recommend the right service based on your engine make, model, and usage pattern.

Do you include a diagnostic scan with scheduled services?

Yes. Every scheduled service includes a full diagnostic scan of your engine's ECU (on electronically fuel-injected engines). This reads stored trouble codes, sensor data, and performance metrics — catching issues that aren't visible during a physical inspection.

Maintenance Service

Scheduled Engine Service in Tampa Bay

Regular scheduled maintenance is the single best thing you can do to protect your marine engine. We handle every major service interval — from 20-hour warranty break-in services to 500-hour major overhauls — right at your dock throughout Tampa Bay.

Request a Free Estimate (425) 829-0305

Serving St. Petersburg, Clearwater, Tampa & all of Tampa Bay

What's Included

Every service comes with our white-glove project management — one point of contact, detailed estimates, and quality-checked work.

20-hour break-in / warranty service
100-hour standard service interval
200-hour intermediate service
300-hour comprehensive service
500-hour major overhaul service
Engine oil and filter change at every interval
Fuel filter and water separator service
Cooling system inspection and flush
Diagnostic scanning and code reading
Impeller inspection and replacement
Spark plug service
Lower unit / outdrive gear oil service
Belt and hose inspection
Compression and leak-down testing (major intervals)

Ready to Get Started?

Contact us for a free, no-obligation estimate. We'll assess your needs and provide a detailed quote before any work begins.

Request a Free Estimate (425) 829-0305

White-glove project management included with every service

Why Engine Hours Matter

Marine engines track their usage in hours, just like aircraft engines. Each hour-based service interval addresses specific wear items and inspection points based on how the engine degrades over time. Skipping or delaying a service interval doesn't just risk a breakdown — it can void your warranty and accelerate wear on components that were designed to be serviced at that point. Our technicians check your engine hours, identify the correct service interval, and perform every item on the manufacturer's checklist — plus additional inspections based on our experience in the Tampa Bay saltwater environment.

What Happens at Each Interval

The 20-hour service is your engine's break-in checkpoint — critical for new and rebuilt engines, often required under warranty. The 100-hour service is the foundational interval that covers oil, filters, cooling, and diagnostics. At 200 hours, we go deeper into fuel systems, ignition components, and drivetrain. The 300-hour service adds cooling system flushes, exhaust inspection, and steering evaluation. At 500 hours, your engine gets a major overhaul: full fluid replacement, valve adjustment, injector testing, and a comprehensive systems check. Each interval builds on the previous one, creating a progressive maintenance strategy that maximizes engine life.

Don't Forget the Diagnostic Scan

Modern electronically fuel-injected marine engines store diagnostic trouble codes, sensor readings, and performance data in their ECU. At every service interval, we perform a full diagnostic scan to read this data — catching issues that may not be visible during a physical inspection. Sensor drift, intermittent faults, and fuel trim abnormalities can all be detected before they cause symptoms. This is especially valuable at the 100-hour and 500-hour intervals where engine health benchmarks are established.

Service Intervals Explained

Each interval builds on the previous one, creating a progressive maintenance strategy for your engine.

20 Hour

Service

Warranty

The initial break-in service for new or recently rebuilt engines. Typically required under warranty, this service includes an oil and filter change, inspection of belts and hoses, and a general systems check to confirm everything is running as it should during the critical break-in period.

Oil & filter changeBelt & hose inspectionFluid level checkGeneral systems review

100 Hour

Service

Recommended

The foundational scheduled service interval for most marine engines. Covers oil and filter changes, fuel filter replacement, cooling system inspection, and a thorough diagnostic check. Keeping up with 100-hour services prevents the most common causes of engine failure.

Oil & filter changeFuel filter replacementCooling system inspectionDiagnostic scanImpeller inspection

200 Hour

Service

Builds on the 100-hour service with deeper inspection of fuel systems, ignition components, and drivetrain. This interval is critical for catching wear items before they lead to on-water breakdowns or more expensive repairs.

All 100-hour itemsFuel system serviceIgnition system checkDrivetrain inspectionSpark plug replacement

300 Hour

Service

A comprehensive mid-life service that includes everything from previous intervals plus cooling system service, exhaust system inspection, and steering system evaluation. Ideal for engines seeing heavy seasonal use.

All 200-hour itemsCooling system flushExhaust system inspectionSteering system checkTrim & tilt service

500 Hour

Service

Major Service

The most thorough scheduled service interval. Includes full engine diagnostic, complete fluid replacement, valve adjustment (where applicable), injector testing, and a comprehensive systems overhaul. This service restores peak performance and extends the life of your engine.

Full diagnostic & scanComplete fluid replacementValve adjustmentInjector testingComprehensive systems overhaul

How It Works

Getting your boat serviced is simple.

Request Service

Assessment & Estimate

We assess your vessel and provide a detailed, itemized estimate. No work begins until you approve.

Expert Service

Certified technicians complete the work with progress updates. Quality-checked and documented in the app.

See our full maintenance process

Save with Management

Management Customers Save on Every Service

Mobile Marina management customers get exclusive discounts on maintenance and fuel, plus proactive inspections that catch problems before they become expensive.