We recently purchased a Polaris EX2100 (2004) w/a Mercury 250 Optimax DFI V6. The warning system sounded for overheating. We flushed the cooling system and cleared debris from the propeller. It still heats up??? Note: The lake water is filled with grass. We've been driving it for two months and have to continually pull grass out of the propeller underneath the boat. Afterwards it runs full speed but then begins to heat up again. ???