Hi Fastmark, thanks for your reply. The original metering plates in the out boards are marked 35. I purchased all 3 carbs new back in 1985. They were reproduction 1969-70 auto carbs. Last year I installed the Promax jet plates and per their suggestion installed the 84 jets in the front and rear. This has not fixed the issue. I do have a new inline filter, and when I rebuilt the carbs last year I made sure that everything was cleaned and blown out. There isn't any inlet(brass) filters on the carbs. That is the way they came from Holley. Unfortunately we just got our first snow yesterday, so I think any testing will have to wait until the roads are salt free again. I really appreciate your help. I don't understand why these carbs worked so well on the 383, and are so different on the 440. I agree that the idle mixture screws on the out board carbs should not affect this issue.