2003 SeaDoo RXDI not starting

[bdavis1014]

Just bought two '03 RXDI with fuel injection. One starts and runs fine, the other, not so much. I noticed that when i start one, it hums, then starts up. With the second, there is no humming sound. I checked the spark plugs, fine. Fuses, fine. Anyone know what might be causing this problem?

Thanks!