What method are you ultrasonic cleaner users using? How long, what temp, what cleaner and the concentration level, and are you using a preclean in carb dip first?
I'm using my Chinese 6L cheapy ultrasonic for the first time w/Simple Green Pro. Diluted about 6:1. 20 mins at 45C. Did a carb dip first, partly because these carbs were black before and I used paint stripper on them and then mineral spirits to rinse. The dip got the rest of the crud off so the carbs were relatively clean before the ultrasonic. I'm a little uncertain about the general cleaning abilities of the ultrasonic. Crossing fingers. Don't fully trust it yet.
I'm using my Chinese 6L cheapy ultrasonic for the first time w/Simple Green Pro. Diluted about 6:1. 20 mins at 45C. Did a carb dip first, partly because these carbs were black before and I used paint stripper on them and then mineral spirits to rinse. The dip got the rest of the crud off so the carbs were relatively clean before the ultrasonic. I'm a little uncertain about the general cleaning abilities of the ultrasonic. Crossing fingers. Don't fully trust it yet.