idles fine will not power up to get on plain[pad]
Have you checked your fuel line, bulb and connections going into the engine? Hope its nothing serious and turns into a quick fix.
Fuel lines and spark plugs just to knock out the simple stuff.
Yamaha's get difficult to troubleshoot as the fuel system is pressurize way above most motors so the smallest amount of air in the fuel system that's not supposed to be there can make a big difference.
After you're sure the fuel system is good, to include the pump, time to inspect the power packs and electrical side.