Offshoreonly.com - 8.2L Running HOT!!

lookin for a little advise. one of my engines SEEMS to be running a little on the warm side (180-185) compared to the other (175). They are closed cooling including the manifolds. i've already replace the exhaust components last year as well as cleaned all the oil coolers and heat exchangers and raw water impellar. there doesn't appear to be any restrictions in the raw water flow. if i shoot the t-stat housing with a laser thermometer it reads from 155-160 degrees. various areas of the engine block and heads are pretty consistent too (around 150 degrees). the temp sender was replaced last year as well as the thermostat. the circulating pump is about the only thing i haven't replaced. my question is should i go ahead and replace the circulating pump or is there some way to test the gauge/sender to make sure that isn't the issue? i don't really know of anything else it could be?? any ideas?