2010 nitro z-7 alarm sounds at low rpm

[Tadlee]

I bought my nitro z-7 new in 2010 and had to replace the fuel line last summer because the ethanal eat it up.  But after that it has ran great until two weeks ago.  It runs great at full throttle, but when I slow down to about 1500-2000 rpm for very long I get a long beep and it goes to an idle.  Does anybody know what this could be?

[Mike Cork]

Assuming its a Mercury motor, a steady tone is an overheat. Check for water flow. Sounds like your water pump may be going out. That or you have a thermostat sticking preventing water flow to portions of your motor.

When you power up, you're increasing water flow preventing overheat. However at slower RPM'S there isn't enough flow.