I am not knowable about stuff at all I just stay in alot of Holiday Express hotels.

Alarms can start in as soon as the engine starts especially low water pressure and or bad water pressure sensor or IAC or its circuits. IAC controls IDLE but still comes into play if bad no matter of rpm.

Other sensors or short circuits can trigger the alarm as well at start up.

Your location

who is working on your app ?

Not a hard to fix for this but again if you keep on running it especially if it has a bad IAC can or will knock out the ECM 555.

I'm in SW Florida.

Funny Holiday Exp reference

Everyone on this board will say IAC the first time you mention you have a problem. They certainly are problematic but not to the extent the board would have you believe.

X2 to what BUP said, go get it scanned and let us know what it says. Even if the person scanning doesn't know what they are talking about we can give you a reality check.

Well I had it scanned today and there weren't any codes so now I really don't know what to do.

Whoever scanned this needs to look in the history of the scan -

Who scanned the engine ? Do they have the experience of scanning marine engines and know what all the information means ?

What scan tool did they use.

If you have an alarm going off you have a set fault code of some sort as the scan should pick it up.

what is voltage from B+ sources with key on not running engine and what is it at idle and 2000 and at 4000 rpms when solid warning horn going off ?

To find my water pressure sensor issue we had to run the boat with the scanner on it and watch the details and narrow it down. there was also no codes on mine. Took about an hour of getting out in the water and running around crossing off possible issues.

Solid alarm will show no matter what, most likely as over speed.

Sometimes IAC will not show a fault code

Had the same problem, my issue was the IAC chip in the PCM. I sent it to whipple superchargers and they repaired it.