Hi Lance, I thought I wrote this post earlier, but I guess I messed up... Anyway, I had the same problem you did, engine was running hot, impeller was fine, no clogs, new thermostat, etc. One thing you can do is just take the thermostat out, if it still overheats then that's not the problem. What I found was that the water primer pump was bad. The bearings had gone out and it wasn't turning like it was supposed to, thus only getting part of the water into the engine. To check that, pull off the outlet hose from the pump and stick it in a 5 gallon bucket, it should fill the bucket in 15seconds, if it takes longer, you need a new pump. I would also suggest calling Discount Inboard Marine and talk to someone there, they know their boats over there, they have fixed mine twice over the phone.
Later
Tiffany
www.WakeChicks.com