iac valve issues
 

I had a problem when i put the the right engine in gear it tries to sputter and die. But if you crack the throttle a bit after you put it in gear it runs fine. So i pulled the iac valve and it was frozen up and was not operating. So i replaced it and when i put the new one in when i started it muliple times do to that it has to relearn itself it kept opening the iac valve all the way open and making the boat idle at like 2200 rpm much to hi.so im trying to figure out what would be making it tell the iac valve to open all the way.oh by the way they are 96 mercruiser 350 mpi

A '96 MPI engine should have a MEFI1 controller, which does not have an IAC learn function. A new IAC valve should work normally after one reset (key on and off).

You may have a bad connection on one of the four driver circuits so the valve can only open and not close. Another possibilty is a vacuum leak because I don't think an IAC can rev the engine that high even when it's fully open.

im pretty sure its not a a vaccum leak cause i can manually set the valve all the way extended and it willl run like it did previously with the frozen up iac. soon as you hook the plugin into the iac valve the engine revs up and when i pull the valve and look at it its fully contracted.