start stop stalls

Ive had issues where it will start and then randomly cut out, as well as it starting without touching the button. I pulled the plug for it and put it on the continuity meter, it shows continuity regardless of the button being pushed. Common sense tells me that its got to be shot, but Im second...

1993 seadoo xp 650 brand new engine, 650 i think, carbs, fuel lines and gas and oil, sat for 3 years, starts and then you let go of the starter button it stalls, if you hold the button down you can rev it up and will stay running good as long as you hold the button down. Need help. This is...