While boat theft nationally increased 1 percent in 2016, there are no national figures for boat engine thefts, according to the National Insurance Crime Bureau.
Florida, which ranks as the top state for boat thieves, does keep track of engine thefts. A CNBC analysis of records compiled by the Florida Fish and Wildlife Conservation Division shows a total of 811 engine thefts in 2016 compared with 643 in 2015. About half the stolen engines were Yamahas.
"I will you tell that outboard theft from marinas, outboard theft from dealers has gone up dramatically," said Dan Rutherford, director of claims and risk management for Maritime Program Group. "In my 35-year career, I've never seen as many outboards and as many units being stolen from as many marinas."
Rutherford, who suspects a number of the engines are being shipped overseas, said the thieves typically break through a fence with a stolen truck.
"And there are three guys usually. And they're just lifting the engines and putting them on the truck beds," he said.
The recovery rate for stolen boats in Florida last year was 36 percent, according to the National Insurance Crime Bureau. In California, the second most ranked state for stolen boats, it's only 55 percent.
"It's a great crime of opportunity," Rutherford said. "It's a difficult crime to solve. The boats disappear."
Miami-Dade Police Sgt. James Barrett said boats and boat engines, unlike cars, are more difficult to track once they are stolen.
"The data is not out there mainly because with boats there's a lot of different manufacturers," Barrett said. "And they come and go. And then once they go out of business, it's hard to get those records. We do have some boat manufacturers that are very cooperative, that do keep good records, and they'll give us a lot of history on that boat. But on motors, it's just a serial number."
Officials from the Coast Guard and local law enforcement told CNBC they have not tracked large number of the stolen engines overseas, at least in recent years. Instead, thieves typically try to replace the engine's sticker with another one, making it appear the stolen engine is legitimate.
Many boats, and their engines, are often easy targets for thieves whether it's at a marina or in someone's backyard. Some 5,115 watercraft were stolen last year in Florida, according to the National Insurance Crime Bureau.
The Miami area is number one in the country for stolen boats, followed by Tampa, Fort Lauderdale, Orlando and Tavares.
"Unfortunately, with the amount of waterways that we have in Miami-Dade County, it is a target-rich environment," said Miami-Dade Police Officer Miguel Espinosa. And sad to say, it is very easy [for] someone to try to steal a vessel. Or engines, especially engines."