This past weekend I took the boat out for the first time this year and everything went well except for the one engine getting hot. I had this same problem last year and I figured that my guage was bad so i didn't pay much attention. Over the winter i put new auto meter guages in the boat. The one engine is reading around 170 on the guage but when I shoot the thermostat housing with my Infrared Thermometer it reads around 90-100 both heads read the same temp, I forget what the temp was but I want to say that it was close to the same and the thermostat housing. Now for the other engine, the guage itself was reading 230-240 but when i shoot it with the Infrared Thermometer it read with in 5 degrees of the other motor and i could touch the tail pipes with out burning my hands. Any suggestions on what to do next, sending unit on the thermostat housing is bad? Hopefully this all makes sense.

Sounds like a gauge or sending unit problem. Try switching the wires from one gauge to the other and see if the problem follows the sending unit, or the gauge.

I want to say that I switched sending units last year but cann't remember what the out come was. Im so forgetful at 29 I can only imagine what im going to be like at 40. I was told that the Infrared Thermometer don't lie thats why I didn't worry about it to much last year and that why I went with new guages over the winter (I told the wife they were all bad) but they didn't seem to be the fix. Ill try to switch the sending units and see what that does.

I would say the sendor. I backed my boat in the water the other day and started port motor and gauge read 250. Freaked me out. It only ran for 15 seconds or so and could touch everything, nothing hot. Looked a little closer and the wire was off the sendor.

impeller 1st,what kind of manifolds,ive seen a lot of stock elbows clogged lately causing overheat
water cant get out of engine

I think ill have to mess with the senders. Impellers were both changed last year, the manifolds are gil style.