overheating question??

[oldfielder]

Are you supplying water through the outdrive or a dedicated thru-hull for cooling this boat?
If it hasn't overheated fully, that's a good thing.
If the boat ran fine at the water but not the driveway, the first thing I would be checking for is restrictions in your water flow. There are many places this could be happening, but one of the easiest ways to check initially is to see if you have good, steady water coming from the exhaust ports on your transom assembly.
I know this sounds ridiculous, but definitely check if your hose in the driveway is compressing anywhere from the suction created by that seawater pump-once it gets going if pulls pretty hard to cool a big motor like that.
It seems strange that you would get home and have this happen after running the boat fine.
If it is fwc, one of the easiest ways to check if you fried the impeller on the seawater pump is to pull the end cap off of intake side of the heat exchanger and see if there is any crap in there-bits of rubber in this case-if there is any, then you will know immediately where your problem is.
As previously suggested, it could be your thermostat, but is seems strange that it would go bad between the ramp and your house, although most stuff that happens on boats happens at the stangest times.
Feel free to pm me if you have any questions-I have the same engine block and may be able to help with further diagnosis.