So I done a little maintence work or I should say my mechanic did to my 6BTA which included a new front crank shaft seal , couple of new engin mounts and a general going over for the season, also replaced the pully belt tensioner and while doing that installed a new belt from cummins to replace the one on there which was after market but 3 years old. Boat ran like a dream till today, about 10 hrs on motor since work was done I was leaving the fuel dock and all of a sudden could hear the racket from the front cowling, Took cowling off and belt was shredded not broken but badly shredded, Lucky I had a spare after market one on board. Checked all pulleys and edges all good no wobbling. What would cause the belt to fail? Could the new pully tensioner be adjusted to tight or is there adjustment on the unit. Thoughts and Opinions Thanks.