runnin hot at idle

[wjoyner]

I've got a 470 mercruiser that we just had to replace a cracked heat exchanger, we have wverything hooked back up hooked the water up to it crancked it up and the unit started running very hot within the first 3-5 minutes, I have checked the hoses to make sure that I have not missed anything and to make sure everything is in the correct place, and it seems to be, but none of the hoses going to or coming out of the heat exchanger are hot and do not seem to be under pressure, but the one going to the water pump is very hot. Should I start with checking the impeller or the water pump?

 

[guyjg]

I would check the engine coolant level first. If it's correct then replace the impeller.