Should I replace my 18 yr old IAC valve?

[fishon195]

Its not malfunctioning, but I heard and read here that it can damage my equally old ECU if left unchecked?

I have no idea how to test it nor do I want to. . Does a new one have to be adjusted or calibrated to my engine after installation?

[DennisG01]

You said you read about it damaging the ECU... how does that happen? What did you read about regarding the reason?

It's a simple plug-n-play on Mercruisers - I can't imagine it would be different, but I also can't say for sure as I have zero experience with it on a Yamaha.

[fairdeal]

Rodbolt has stated that -on at least some models, don't recall which -
the ECU can overheat/be damaged due to a non-responsive IAC valve.

Changing the IAC on the F115 (same as the 6-throttle body F200/225)
is trivial; 3 Phillips screws and a wire connector,
no "settings" or "adjustments".

Personally, so long as I heard it rattle every time I tuned off the engine,
I wouldn't replace it "proactively".
Not at $409 list....

[DennisG01]

I wonder what is different about it (and the function?) compared to the IAC on a Mercruiser? The only thing that happens on a Mercruiser, if the IAC fails, is you can't start the engine in neutral... hence the "idle" air control. You have to start the engine with the throttle advanced and then quickly back to neutral and into gear to avoid stalling. Awkward, but not that big of deal.

And...Geesh... $409 list is almost 4 times what the Merc one is! And the Merc one is really just a Ford IAC (even though the engines are Chevy-based) that you can get at NAPA for a fraction of the cost.