Another Alarm question

E

ereediver

New Member
Jun 17, 2009
16
Ohio
Boat Info
300 Sundancer 2004
Engines
5.0 MPI Merc. Bravo III
I have a 2004 300 Sundancer with bravo III engines. It has the smart craft speedometer guages. When at slow speeds all is well. When we throttle up top get on plain an alarm starts. It is two quick beeps every minute. If you stop shut off the engines and stay off plane, it does not sound. All temps, pressures, and fluid levels look to be okay. Any suggestions on where to look.
 
I guess I'm not the only one who is stumped..:huh:
 
There are many things it could be.

A merc mechanic will have a diagnostic tool that they can plug in and determine the exact issue.

If I were to guess, I mean just give a wild ars guess, the IAC’s go out so darn often I’d check that first but the correct answer is to have a mechanic plug in a diagnostic tool or buy one and a code key.
 
My 2beep/min was because of a fault shift interrupt switch. The switch would get warm/hot when operating and then go from "in gear' to "neutral" and then back while up on plane only (above 3,100 RPM). As a result the ECM would throw and alarm (there was a 5% power reduction that I did not notice). The only way this was discovered was by having a tech with the CDS on the engine while it was running up on plane. This particular type of fault was not the type that would store a code in the ECM after the engine was turned off (was not a "sticky fault").
 
Thanks all for the replies, was hoping to avoid the mechanic, but looks like it might not be possible.
Although what DaleM describes sounds like my exact problem. How hard is that to change?
 
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It in itself is super easy. It sits on top of the engine and is near where the throttle cables come to the throttle body. I was told there is some way to adjust it but I don't know what that is. Mine had two purple wires coming out of it. It's like a $29 part. I chased that damn alarm for weeks and was so frustrated when they told me that's what it was!
 
Thanks DaleM, I think we have the same engines. That fix seems cheep and easy enough to give a try. I appreciate the help. If I remeber right, the switch just plugs in.
 
Yes there is a basic connector. Jus unplug and replug the new one. Again I don't know the alignment part of it.
 
I was just posting to say we did located the problem. It was the gear indicator switch on the port engine. The switch is fine, but it rests so close to the egde on the "Shift Lever" not sure if that is what it's called, that rough seas knock it of and makes the computer think the engine is in neutral, but still running.
Now having a hard time adjusting the lever to fit under the switch as it looks the switch is fixed, you have to adjust everything else on the lever to move it to the right place. Anyone know a trick do do that?
 
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I'm happy you found it! When you get the adjustment part figured out could you let me know? The mechanic that found mine said something about using a certain sized drill bit as a spacer. Is the process in the shop manual?
 
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