I just took my Sophia J-450 apart and cleaned some clogged jets and fired it back up and it starts up fine but when about quarter throttle or coming down from half throttle it makes this sputtering sound. It looks like I'm not getting a smooth trail of smoke but sometimes it sends out puff's of smoke. I have tried adjusting the needle valve for the oil and didn't help the sputtering. Any suggestions?

Thanks,

Barclay