Got a 2010 ( that's when I bought the boat) 50 ELPTO, 2 stroke, Ser #18761365, Mod # 1050412FD. I had it out on the water yesterday, cranks fine and idles fine. When I throttled up I was cruising at around 4200 to 4500 rpms when the engine just powered down to about 3000 rpms, didn't die it just...