They never returned our calls (dozens of calls)Showed up a week lateDid a horrible jobCharged us 400% of the quoted price but said everything went wellOn the one hand they convinced me to do all my Volvo Penta work myself since I am done using vp dealers

These people care about cruisers. They are happy to help people from out of town that are in need. I was traveling with my family when I needed their help, including 3 young kids, and they seemed to really care about that.And, of course, they are smart. Among other accolades, they are best Volvo mechanics in the Keys if not a broader area.

Mark, Megan & all the crew are true professionals. Best in south florida

Best place on Earth. Bar none

Best in the world.

The owner Mark is the real deal. This old school mechanic knows his craft like no one else in Key West. If you have a 5 million dollar boat, or a 5,000 dollar boat, you get the same service. Hands down the most knowledgeable diesel shop and custom systems fabrication shop. The shop stands by their work, and has a legendary reputation for a reason. Complete re-powering service, and Yanmar and Volvo warranty work. I can not speak highly enough of the supreme quality of work done here.

Great parts store next to the Perry Hotel. Very knowledgeable and super helpful. Tons of engine parts.

Mark is an AWESOME mechanic! He has been in the business for 40+ years. You can call him or email him your problem and he will be happy to guide you. He has done this for a few boats who were cruising around the world. Even sending them the parts they needed.

Great place. Awesome staff. They care about helping the customer first. Thanks guys.

Knowledgeable, friendly, kind and professional staff. The guru at the end of the quest. The associates ready to enable the guidance and goodsense provided.

My twin Yanmar 2014 3YM30 diesel engines were experiencing overheating issues and not discharging appropriate amounts of raw water from the exhausts. I stopped by Marine Diesel and Mark graciously spent thirty minutes with me discussing my engine issues, at no charge, offering advice on things to check and a plan of attack in solving the engines overheating issues. Another vendor wanted $125 to come and give me a quote. Not so with Mark. He and his team Meagon, Tyler and Chris all who worked with me did an excellent job of cleaning my two heat exchanges, pressured tested and promptly returned to me within 24 hours at a very reasonable price. They also provided me professional critical tips on how to clean the internal engine block cooling system. I had heard terrible things about diesel mechanics on Key West/Stock Island but after reading Marks other reviews here I decided to give him a try. Am I glad I did. No hesitation in recommending him.

Best Diesel Mechanics in Town!

It was great he is a very smart man.

Mark is a man of honor and respect. When I experienced problems with my Kohler Marine Generator (which actually has a Yanmar diesel for the power) I went to his place of business for help. As much as I wanted Mark himself to work on my equipment, he was swamped with other work and was unable to be the mechanic on my job. Everyone wants the best, but I understand that is not always possible. After repeated attempts for Mark, another person in his employ at the time came to my boat. To say the least, his service was subpar and not the kind that Mark is known for. After a period of time of it not getting repaired, I had to seek other means of repair. Thru another one of Marks employees, he became aware of this. This subpar employee is no longer with his company and Mark himself personally made it a point to correct this even offering to repay me for the services someone else had to provide me. We all make mistakes, but how we handle a mistake is the measure of both good business and a great person. Mark and his company are just that! In the event I ever need the services of a Yanmar mechanic in the future, I would call Mark at Marks Marine Diesel of the Florida Keys without hesitation!

Very cool location.