That was a tough problem without a computer to read the ecm. I had this boat on the water last summer and didnt have a problem with idle or anything really. So having it down over the winter and changing the engine I didn't think it could be anything sensor related. My mind was fighting me on this. Thinking back the old engine ran rich at idle and kinda stumbled from 3500 to 650 but I assumed big block kinda normal. Sometimes I'd have to run it to get it to clear up. Now it idles smooth and low.

If anyone remembers my ordeal with this boat from my past post you will know by now I believe she may be cursed so if anyone has any advice on how to uncurse a boat I'm all ears. Im thinking I need to change her name maybe that will help.

Glad its fixed

Glad you found it, we knew the IAC didn't have control of hot idle, we just didn't know why. The fact it reset though to idle target hot on a key cycle has me puzzled though if it wasn't cycling at all. Must be when it hit the higher timing after revving it up as to why it wouldn't return. Glad you can move, Smitty