I bought this 150vmax a couple months ago and haven't been able to get it dialed in yet. main issue is idle. basically the motor runs great up on step, you can hear it skip just a little bit when you first begin to give it some power. at idle though it runs for a bit(sounds rough) then dies out. while idleing tho if i press the key choke in it keeps her goin. before i bought it i think it sat for about a year. could the carbs just need to be cleaned??? fuel pump??? any info would be helpful.