I was woken this afternoon to help get my dad out of the lake since he took it out for the first time since the winter. He was going across the lake and suddenly his motor mad a bump sound and is locked up. Has an 1985 Searay with a GM 350 in it. I made it about half the distance as he did when suddenly mine made a poof/bump noise and just quit. I looked at the guages all was fine. Temp/Voltage/Fuel. Checked the oil it was perfect and new. I just replaced the plug wires on it since it was jumping fire to the block and was causing it to miss sometimes. Apparently that was fixed since the motor ran great when I hit the water before it suddenly died. I get the boat back home and start the process of elimination. It turned over a couple times. It was getting fuel you could tell it had plenty of compression. I started suspecting it not firing. After checking for fire the engine if cranked again. I pulled the distributor cap and attemped to turn the shaft. Wola. I could turn it and even fell it catch sometimes. So I pulled it out and sure enough the gear is striped. I hope the cam is fine. The real questions is what lead up to this to happen? The only other thing we had done to the boats was change the lower unit grease. We are using the same kind. I wonder if its possible it had something to do with it. Dosent seem likely though. I just wanted to here others thoughts on it. Could the engine some how seized and caused the shaft gear to get stripped or did it just simply fail? Normally the motor would start at the bump of the key everytime until now of course.