Hi all, first time poster here. My 1997 150hp Evinrude started running hot at idle last weekend, up just over 200 deg but the alarm doesn't sound. As soon as I get up on plane the temp goes down to normal levels. The telltale stream is strong and the water pressure is good according to the gauge. I just replaced the thermostats but this didn't change anything. I had the water pump replaced the middle of last season so that should be pretty fresh. Could the impeller be shot already? I did run aground at idle speed coming home one night in the dark after I strayed from the channel so I guess I could have sucked up some sand/ seaweed then. I have flushed through the flush fitting but no luck. Is there a screen behind the plastic grates that cover the water pickup that I can clean up? Any thoughts would be much appreciated. I'm supposed to be taking my boss & his wife out this weekend and would hate to cancel.<br />Thanks Guys!