Rev alarm

[Rinker12]

2013 rinker bravo 3. Mercruiser 5.7 mag. At 5000 rpms throws alarm. We changed o2 sensors and spark plugs , thermastat, temp sensor unit and still alarms

 

[Fun Times]

At 5000 RPM you might be surpassing the Rev limiter in which would sound an alarm on fuel injected engines.

On top of the engine there should be an engine informational type sticker with the RPM range mentioned for your engine model... What does yours show?

Also note that your RPM gauge might be reading a bit off depending on type of gauge you have. (Analog or Digital readouts?)

 

[Rinker12]

Its analog, taking to scan see if codes and will clean wires on gauges. They keep coming loose. Will make sure thermastat not stuck open again. This frustrating it run fine other than that

 

[Fun Times]

taking to scan see if codes

That or you could try renting a scan tool version so you can see what's happening at RPM if you're in the USA i believe it is,

7 day RENTAL of Rinda Diacom Marine diagnostic cable & software | eBay

This is for a one week rental of a Rinda Diacom marine diagnostic cable and software. Note that not all adapters are shown in the picture. This tool will allow you to view and diagnose many things on marine engines.

www.ebay.com