New to Mercruiser have 1994 3.0 LX Buzzer intermittently sounding H2O Temp & Oil Press gauges normal

[JCL93m]

I bought a 1994 Wellcraft Eclipse 18S with Mercruiser 3.0 LX project boat engine would not start electrical all messed up got that squared away and had bellows and water pump changed installed new control box and cables took boat out first time on the water intermittently hearing a buzzer sound sometimes at high RPM and sometimes at Low RPM indiscriminate. Water Temp gauge is at 160 and Oil Pressure at 35-40 PSI. What things can cause a buzzer on this engine; I do not have a manual yet... Thank you!

 

[dubs283]

Gear lube monitor (if equipped), temp, oil pressure

 

[nola mike]

Disconnect one at a time the temp sensor and oil sensor to see if either/both are sounding the alarm. They're different from the gauge senders

 

[JCL93m]

Disconnect one at a time the temp sensor and oil sensor to see if either/both are sounding the alarm. They're different from the gauge senders

I got to get a shop manual so that I can identify the sensors and disconnect them as you suggested, I'll order one today...

Thank you!