As I was moving on the lake, the motor started throttling down and died. It would not restart after that. Nothing unusual happened. Nothing sounded different. Just died and would not restart

What year model is it? EFI, Di, Optimax?

2002 efi

that's a tough one for a key "board fix"... will it turn over?.. could be as simple as fuse, kill switch and/or circuit, harness ta fuel delivery ta something else electrical....
needs a comp test first thing.. have seen burnt piston/pistons bring a motor ta stop without any strange noise at all..

if it turns over, start with this ta eliminate a coupla things..
take tha cowl off and stand by tha port side of tha motor payin' close attention ta tha vst (silver lookin' canister lookin' thing...
have your better half or bud turn tha key on..
fuel pump should come on and run for 30 sec. or so...

another test for those that don't have tha tools/meters and such for fire is this..
take a small "squirt bottle" of sorts with a 50 ta 1 (at least) fuel mixture in it..
open throttle a little, put 3 or 4 squirts of tha mixture in tha butterflies on tha back of tha plenum then hit start... if it fires at at all it will narrow down tha problem some..

almost forgot.. anything ya do that MIGHT start tha thing, make sure ya got tha hose (water) to it!

jus saw your "other post".. if your gonna have it looked at try Gunter Marine on Jacksboro highway Ft Worth if ya don't wanna go ta Alvarado....

Started checking things early this morning. Think it's a bad fuel primer bulb. Changed it out and it started right up.