So I took out my gp for the 2nd time this season and I was having some problems. Before I left my house I fired it up to make sure it ran, It fired up and was bogging out until it backfired and then it ran fine. I thought nothing of it and left for the river. When I got there I launched it and it was running good, I drove it the 1/2 a mile down the river to the beach and beached it. I chilled out for about 10 minutes then I went back out It was running fine for the 1st few minutes then while I was at 30mph it just shut down. I started it back up and it would get up to speed but then shut down. After the third try I started it once more but when I went to crank it it wouldn't turn over. The starter would go but not turn it over. I got a tow back to the beach and let it sit and tried to get it out again but the exact same thing happened. It would run then die and then lock up. So I get it up on the trailer to head home and start it one last time to get the water out and it was backfiring and not running good. The engine had been running awesome all of last year with no problems and ran last week with no problems either. Has anyone every experienced this before? I'm stumped on what the problem is, I was thinking electrical or a twisted crank or something like that? 
Thanks for the help!
Thanks for the help!