Our 96 Sea Doo GTX with 787 motor started running rough and stalled a few times. Charged the battery and it would not start. Sprayed a little starting ether in it and got it running so-so. While out riding it was on reserve not main tank. Ran out of gas on the reserve and switched it over to the main tank. It would not restart. Checked compression and it was 150 in one cylinder and 30 in the other. Did a wet reading and it was only 35. Took off the spark plug and one was plated with aluminum. Removed the head and the piston had a small crater in it where the aluminum was eated away. What could have caused this???