On Thu, 3 Jun 2010 12:33:59 -0700 (PDT), J wrote:

I have a 2000 four winns 230 hrizon, and i am having an issue with it
over heating. I hooked it up to a manual temp gauge and it is running
around 230. I have checked everything i can think to check. we pulled
the impeller off the fresh water pump that pulls the lake water into
the engine and this rubber gear is in perfect shape. We pulled the
pump off the front of the engine and everything appears to be ok
there. We pulled off each individual cooling hose and checked for
blockage and there was nothing to be seen. Can someone please give me
some suggestions as to where I can look next to fix this over heating
problem. I even ran water backwartds out of the outdrive to check for
blockage and there appeared to be none.
THanks in advance
Justin

Have you tried a new thermostat?