I have a 99 yamaha Waverunner?

The waverunner was working great a couple of weeks ago, it sat for about a week while I was on vacation and now it attempts to start but does not quite make it. I replaced the plugs, the battery is new, I know the battery is not bad I just put a brand new one in, I thought it may be low and jumped it which usually worked when the old bad battery was in there, still nothing.

Does anyone know what could cause this problem or if there is anything else I need to check out with regards to this issue?

Karyn
October 2008