Mercury 250 Optimax 2B402441: 3 beep alarm only once today

[c_m_25]

Hey guys. Took the boat out today and was idling to our first spot. Maybe a 1/4 mile at idle speed. Almost get there and I get 3 beeps. I cut the motor and search it up and it looks like an oil alarm? I checked my external tank and it was full. I idled back over to the dock and didn’t get the alarm again. Pulled the lid and checked the oil tank on the motor and it appeared full. We fished the rest of the day without issue. Any idea what could have happened?

[lpugh]

Thermoset stuck open, idle for 5 minutes without reaching 120 degrees will set a code and a 4 beep alarm.
Scan computer fault history will confirm if this was the case.
Got to those temps, cold seize risk here.

[c_m_25]

But I got a 3 beep alarm after a long cruise at idle. Temps were definitely at 120 or higher.

[EuropeanAM]

What that means is NON-CRITICAL WARNING: Proceed safely back to port and have engine serviced as soon as possible.

Avoid running the engine until the fault history has been read and addressed.

[c_m_25]

Well, had the motor hooked up and looks like it threw a thermostat fault code. Thinking back, I do remember looking down at idle and notice the temp was around 140-150 but quickly came down. Didn’t think much of it at the time. Good water pressure all day. Will be replacing both thermostats in the heart of spring fishing season. Down 2 weeks. ��

[EuropeanAM]

Thermostat fault occurs when the engine idles for at least 5 minutes and one (or both) banks FAIL TO REACH MINIMUM OPERATING TEMP.

Usually caused by a thermostat stuck OPEN, one that failed to close, or one that leaks due to damage (caused by hard debris).