The crank shaft on my 3156LPSTP broke @ 708hrs. I've owned the boat since 12/2007 purchased with 338hrs. I never had any problem not impact problems nor have I ever hit anything. This caused me to undergo a rebuild. Has this ever happened to any other 315LP STP. And should Yanmar have covered part or all of the repair. Even though Its passed the 300hr warrenty?