If you disconnect the cable from the back where that latch is that hold it . If you remove that and let the cable loose does the idle change or does it stay the same ? IAC does control most of the idle circuit , but just a quick check of things like air leaks and linkage adjustment should firm up the dial and how much have you driven the boat ? Run a couple good laps and just return to neutral and see if rpm drops


Sent from my iPhone using Tapatalk