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Mercury 600/700 IAC Protection

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We aren't happy until you aren't happy
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negative. i just had a 350 mag a couple months ago with an iac failure that fried the wiring harness and damaged the ecm. (melted the terminal connection where the wiring harness plugs into the ecm) in this particular instance, the customer thought the alarm was a bad depth sounder and continued driving the boat for some time. the engine would only occasionally stall.

It does not happen often on any engine, but is not completely unheard of either. All fuel injected engines that still use a physical throttle cable are equally susceptible.

This didn’t really dawn on me at the time of the original thread, but I saw this pop back up and wondered why it would be the same situation with everything that uses that combination. I drove mine with a bad IAC for about 20 mins.
 

Shlbyntro

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This didn’t really dawn on me at the time of the original thread, but I saw this pop back up and wondered why it would be the same situation with everything that uses that combination. I drove mine with a bad IAC for about 20 mins.

When I said a while, i believe the fault history was showing iac issues spanning back for over 10 running hours. 20 minutes is a blip, just dont keep running it all summer without addressing it.

Alot of times, an IAC fault will only present as an intermittant beep every 2 minutes and the engine will be governed down to 95% power, almost unnoticeable to somebody unfamiliar with what the alarms mean
 

nganga

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Earlier I mentioned the fuel system theory. Here’s the actual Mercury schematic

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