the boat fires then dies, if I give it some throttle it runs but rough, I believe it is the IAC valve, I ordered another one it will be here thursday. I do not know how to calibrate it....Do i just stick it in and power it up or do i have to get a programmer, if any one knows please advise...THNX

just put it in, and turn the key to the on postion but dont start. wait 5 seconds then turn off and your good. I had the same problem as you on my 502MPI. It ended up being the stone filter on the inlet of the IAC. I just cleaned it out with brake cleaner and ran good.

Thank you for your reply ..Yes i do have a 502 mpi ,,, How did you know? ..I left it simple and did not explain what the IAC valve was so I was sure to get a response from a knowledgeable source. Thank you