operating temp fluctuations

So my operating temp is usually 160 and doesn't move much at all. Lately when surfing as soon as I come off the throttle to idle, operating temp spikes about 15 degrees and I smell the engine running hot. After a little temperature returns to normal. All throughout surfing engine temp is stable. Week long vacation to lake Norman next week and I don't want this to be a precursor to something more serious. Any help is greatly appreciated. Surfing with 750 in locker, 400 up front, 3 people in boat with driver, stock prop.

Is your impeller old, do you have water strainer. When you idle down after running hot the impeller flow pressure is reduced and I believe it is normal for a temperature rise. Mine is usually 6-9 degrees. If I rev the engine in neutral the temp will drop back immediately otherwise it takes about 30 secs for it to drop back down. An increase in this spike may indicate a wearing impeller. Make sure you have a spare. A water strainer will increase the life of your impeller

So i replaced the impeller, checked the water strainer, tightened up any and all hoses i could find. This is still happening and I'm still seeing a lot of steam(it has a very mild odor) coming from the exhaust when were running a significant amount of weight(2250lbs surf and wake). Any other ideas

Check not just the water strainer, but the entire intake system. It might be clogged somewhere.