I've got a buddy with an older sea ray with chevy sb that he rebuilt last year. He had the cylinders bored and honed, new pistons/rings, head job, pretty much everything. He and his buddies assembled the engine. He ran it a couple of times last year, but said it wasn't running super good, he thought the new carb needed some adjusting.
This year, he took it into the shop, and they put new plugs in, new wires, cap and rotor, and adjusted the timing. When he took it out he said it was doing fine then gradually started slowing down till as fast as he could go was 30mph. He checked the plugs, and found cylinder one plug hand tight, took it out and the electrode was completely cooked, or burned down. When he took it to the shop, the guy checked and found two cylinders with low compression and the other plug was the same.
My buddy pulled the heads now and found both of those pistons were crumbling and coming apart, whatever you wanna call it. Did this happen from a head gashet or intake gasket not installed correctly? Water in the motor, would this do that?