60 hp Mercury EFI overheating (???)

[d@ylm]

Curious if anyone has had similar problems with their engines. We've been told the impeller (?), fuel pump (?), thermostat sticking (?), possibly to thin of oil... maybe a different prop
Boat will be running fine... shut it off and go to restart it and when you get about 3/4 throttle it starts hesitating and beeping.

 

[Texasmark]

A solid beep is over temp. An on and off cycling beep is low oil in oil tank. Oil is TC-W3 available at Walmart sporting goods. Thermostat could be sticking which would cause problems below 2500 rpms. Above you have a pressure relief valve that opens and allows full flow, pressure, not temperature controlled for increased cooling.

If those two valves are functioning properly your water pump impeller (rubber toothed centrifugal force pump impeller) is worn out. If that's not the problem you have either ingested sand or seaweed, or such, or you have a buildup of corrosion in the water jackets....if you operate in salt water.