I purchased a new Yamaha boat engine ( Model F200XB / Ser. # 6DAX-104204) on a Robalo 21 6/19/2020. I used the boat and engine for a total of 15 hours. I launched the boat a few weeks ago and the engine sputtered and died out within a few minutes of outing and began to smoke. I did not hear any audible alarm nor saw any alarm issues on the boat operation console. I was towed into the dock. I took boat and engine to a Yamaha dealer at the Kona Coast Marine shop and have dealt with the owner Gary - Ph. [protected] / [protected]. I am told by Gary that the impeller malfunctioned and did not cool engine as a result many parts of the engine melted and burned up much of the engine. Gary could not find any debris in the impeller nor any external damage that may have caused engine to malfunction.