Marine Diesel Repair, Diagnostics, Overhaul, Maintenance and Performance

in the Florida Keys

Marine Diesel Specialists

Marine Diesel Repair

Marine Diesel Maintenance

Marine Diesel Rebuilding

Diesel Mariner Performance


Complete Marine Diesel Services for Repair, Maintenance, & Performance in the Florida Keys

Marine Diesel Engine Services

Electrical, Cooling & Fuel Services

Turbocharger Rebuilding

24/7 Emergency Services

Mobile Marine Service - We Come to You!

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Marine Diesel Repair

& Diagnostics

Trust us for complete diagnostics and repair for any diesel marine engine.

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Marine Diesel

Overhaul

Our factory trained techs will restore your marine engine’s performance

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Marine Diesel Maintenance

& Performance

Get more life and power from your engine with our expert services.

Florida Keys Marine Diesel

Why Boaters Across the Florida Keys Choose Florida Keys Marine Diesel

Since 2017, locally owned Florida Keys Marine Diesel LLC has been providing expert marine diesel engine repair, maintenance and rebuilding for vessels throughout the Florida Keys.

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Experienced, Factory-Trained Marine Diesel Technicians You Can Trust


With more than two decades of combined experience among our factory trained technicians, our team is equipped to handle any problem your boat may be experiencing. Whether it’s time for routine marine diesel maintenance or a complete marine diesel engine rebuild, you can rely on us to deliver exceptional results. As a mobile marine mechanic in the Florida Keys, we make it easy to care for your vessel, no matter what engine it’s running. We are an authorized sales and service dealer for MAN Marine Diesel engines, and also cater to MTU, CAT, Mercury, MerCruiser, Volvo Penta, ZF, Yamaha, Evinrude, Suzuki, Honda and others as well. To learn more, or to request an appointment for diesel marine service in the Florida Keys, please don’t hesitate to give us a call.

Serving the Florida Keys & Surrounding Areas


Key Largo • Islamorada • Marathon • Key West • MiamI

As a local marine diesel business, the crew at Florida Keys Marine Diesel takes pride in servicing personal and commercial vessels docked or stored in Key Largo, Islamorada, Marathon, Miami and throughout the region. To ensure we are able to provide the best diesel marine engine services in the Florida Keys, we invest in ongoing training and modern equipment. This includes computer diagnostic tools that allow us to service, repair and improve performance of all types of engines. If you are encountering any signs of engine trouble, or if it is time for marine diesel maintenance in the Florida Keys, don’t hesitate to give us a call at 786-619-4720. The professional boat engine mechanics at Florida Keys Marine Diesel are ready to help you get back on the water.

24/7 Emergency Service


If you’re in immediate need of service, we offer 24/7 diesel marine repair in the Florida Keys. Give us a call for fast service. Whether you’re stranded or prepping for a charter, our team can ensure your vessel is safe and reliable.

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The silver, metallic logo for MAN, featuring the letters
The MTU company logo: a blue parallelogram containing the white letters
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Customer Reviews  |   Your business is very appreciated.

G and stars

Mike is an awesome & amazing mechanic, very honest and gets straight to the point!! He’s been serving my 90 ft yacht for a while and no complaints. Truly the best.


- Captain M.

Blog  |   We invite you to monitor our News Blog for informative articles.

By Florida Keys Marine Diesel LLC • October 15, 2026
A marine diesel engine is built to provide dependable power in demanding conditions, but even durable engines require consistent care. Saltwater exposure, long operating periods, changing loads, and harsh marine environments can place significant stress on engine components and supporting systems. Preventive maintenance can help identify developing issues before they turn into major failures that leave you stranded on the water. At Florida Keys Marine Diesel LLC, we provide expert marine diesel engine service in the Florida Keys. Here are four tips for preventing major problems with your marine diesel engine. Follow a Regular Maintenance Schedule Routine maintenance is one of the best ways to protect a marine diesel engine. Follow the manufacturer's recommended service intervals for oil changes, filters, belts, cooling system components, and other critical parts. Marine engines often operate under demanding conditions, so postponing scheduled maintenance can allow wear or contamination to progress unnoticed. Keeping detailed service records can also make it easier to track upcoming maintenance needs. Monitor the Cooling System Marine diesel engines depend on effective cooling to control operating temperatures. Check coolant levels and inspect hoses, belts, pumps, and related components regularly. Raw-water cooling systems also require attention because salt, debris, corrosion, and mineral buildup can restrict water flow. Overheating can cause severe engine damage, so investigate rising temperatures or unusual cooling-system behavior promptly. Check the Lubrication System Engine oil reduces friction and helps protect internal components from excessive wear. Check oil levels regularly and follow the manufacturer's recommendations for oil type and change intervals. Pay attention to changes in oil appearance, unusual consumption, or signs of leaks. Using the correct oil and maintaining proper oil levels can help protect critical engine components during extended operation. Address Warning Signs ASAP Unusual noises, excessive smoke, reduced power, difficult starting, abnormal vibrations, and rising engine temperatures should never be dismissed. These symptoms may indicate developing problems that could become more serious if the engine continues operating under stress. Prompt professional diagnostics can help identify the source of a problem and allow repairs to be completed before a minor issue becomes a major engine failure. Marine Diesel Repair & Maintenance in Key Largo, FL For expert marine diesel engine repair and maintenance in Key Largo , contact Florida Keys Marine Diesel LLC at  786-619-4720  . Our team provides top-quality marine diesel service for boaters throughout the Florida Keys. Feel free to give us a call to make an appointment!
By Florida Keys Marine Diesel LLC • September 14, 2026
Keeping a marine diesel engine in reliable condition requires regular maintenance, accurate diagnostics, and quality repairs. Because your boat depends on its diesel engine for dependable performance, choosing the right mechanic is an important decision. Not every mechanic has the same experience with marine diesel systems, so it helps to know what qualities separate a trustworthy specialist from the rest. Here are four signs you've found a marine diesel mechanic you can confidently rely on. Specialized Marine Diesel Experience Marine diesel engines have different operating conditions and maintenance requirements than general diesel engines. A trustworthy mechanic should have specific experience working with marine diesel systems and understand the challenges associated with saltwater, moisture, corrosion, cooling systems, and extended engine operation. Ask about their experience with your engine's manufacturer and model before authorizing significant repairs. Thorough Diagnostics A dependable mechanic doesn't simply replace parts based on a guess. They take time to understand the symptoms, inspect relevant components, and use appropriate diagnostic equipment when necessary. Thorough diagnostics can help identify the actual cause of an engine problem instead of simply addressing one symptom. This approach can prevent unnecessary repairs and help ensure that the correct problem is being resolved. They Explain Repairs Clearly A trustworthy marine diesel mechanic should be willing to explain what they've found and why a particular repair is recommended. They should communicate in language you can understand rather than overwhelming you with unnecessary technical terminology. A good mechanic can discuss the condition of your engine, explain available repair options, and answer questions before work begins. Clear communication helps you make informed decisions about your boat. Honest Estimates Unexpected marine repairs can become expensive, making transparency particularly important. A reputable mechanic should provide a clear estimate whenever possible and explain what the quoted work includes. If additional problems are discovered during a repair, they should communicate with you before performing significant additional work. Honest pricing and straightforward communication can help establish a long-term relationship based on trust. Marine Diesel Repair in Key Largo, FL For a trusted marine diesel mechanic in Key Largo , contact Florida Keys Marine Diesel LLC at  786-619-4720  . Our team provides mobile marine diesel service for boaters throughout the Florida Keys. Feel free to give us a call to schedule an appointment for expert marine diesel repair or maintenance in greater Key Largo!
By Florida Keys Marine Diesel LLC • August 13, 2026
Because marine engines operate in a harsh environment where moisture and heavy loads are common, even minor issues should be taken seriously. Recognizing the warning signs early and having them professionally diagnosed can help prevent more expensive repairs while also promoting safe boating. At Florida Keys Marine Diesel LLC, we provide expert marine diesel engine repair in the Florida Keys. Here are four common marine diesel engine problems that should be addressed as soon as possible. Engine Overheating An overheating marine diesel engine is a serious issue that should never be ignored. Common causes include a clogged seawater intake, failing water pump, damaged impeller, heat exchanger issues, or low coolant levels in closed-cooling systems. If the engine temperature rises above normal, continuing to operate the vessel can cause severe internal damage. A marine technician can diagnose the source of the overheating and restore proper cooling system performance. Hard Starting or Failure to Start If your marine diesel engine becomes difficult to start or won't start at all, the problem may involve the fuel system, battery, starter motor, or electrical connections. Professional troubleshooting is important because several different systems may contribute to starting problems. Excessive Exhaust Smoke The color and amount of exhaust smoke can provide valuable clues about engine health. Black smoke often indicates an overly rich fuel mixture or restricted airflow, blue smoke may suggest oil is entering the combustion chamber, and white smoke can point to water intrusion or incomplete combustion. Persistent smoke should always be inspected promptly, as it may signal problems that can worsen if left unresolved. Fuel System Problems Marine diesel engines depend on a clean and properly functioning fuel system for reliable operation. Clogged fuel filters, contaminated fuel, failing injectors, or malfunctioning fuel pumps can significantly impact engine performance. Water contamination is another common issue in marine fuel tanks. Regular inspections and timely repairs help keep the fuel system operating efficiently. Marine Diesel Repair in Key Largo, FL For expert marine diesel engine repair in Key Largo , contact Florida Keys Marine Diesel LLC at  786-619-4720  . Our team provides top-quality marine diesel service for boaters throughout the Florida Keys. Feel free to give us a call to make an appointment for expert marine diesel repair or maintenance in greater Key Largo !