Motor is a 2006 with 1200 hours all saltwater. It has only been about 25 hours since new impellor, oil change, new thermostat (it was very corroded in there). Took the boat out today and just a few minutes into idle still tied at dock I get an overheat buzzer and red light. Turn motor off and wait 30 seconds or so before turning back on. Run 20 miles between 3600 and 4100 rpm with no issues. Ocean is flat calm so decided to bump it up to around 45-4600 or right when you hear Vtec kick in. 2 Minutes go by and BAM another overheat light and buzz. Waited a couple minutes turned motor back on and kept it under 4100rpm for the rest of the day and total of 120miles and had no more overheating issues.
What could cause this type of overheating
What could cause this type of overheating