Help on Yamaha Ls2000 year 2000

[GsxrPete]

I purchased this boat first time owner and thought this one would be alot of fun. With that being said I took it to the lake for my first ride and it didn't start found out i was using 1 of 3 safety keys or i saw some one post lanark keys that attach to your wrist. First one started on engine only after playing with it and about to give up and put it back on the trailer. I tried a different one it started both engines and I rode out of the wake away only to go a little less then half throttle. So I used it as a floating radio the rest of the day. When i got home i noticed the key got thicker first one i tried real slim second one a little wider. Didn't think to try third one cause during the cruise at 10 miles an hour one engine shut off but later after floating in one spot for a while turned back on. Does the keys have anything to do with the throttle response ? Would the thickest one give me full power or is there something wrong with it and how can I get it to do 55 or close to that to enjoy it and not be upset with myself for buying junk. Any clues or help with this is grateful. Really short on funds used it to buy it thought that at this price it would be turn key for the family to enjoy for a few years. I'm located in los Angeles California.
Thanks in advance

 

[dyfanf]

The kill switch should only disable the motor(s) entirely, not make them work half-way. However, I have only looked at one LS2000 (and bought my SeaDoo instead) so I'm no expert. I would think you want to use the thickest one that easily engages the switch to ensure a positive connection.
I'd check all the wiring from the switch and to the starters and ensure everything is snug. I'm sure some folks with LS2000 experience will chime in in a bit. Welcome to boat ownership!