Overheating issues

[madiphoenix]

I put my 1992 Four Winns 280 equipped with twin 5.0L Mercruiser Cobra engines in the water early this year, and both engines overheated. Upon firing them up, water poured from the props but temps still climbed to about 210 degrees F before I shut them down, no leaks anywhere. I'm new to these engines, so i'm wondering if I messed up the thermostat install or if they need some kind of priming after layup. Any ideas on what to check next?

 

[nappa]

I think you should first start by checking the impellers since a worn or damaged one can cause overheating right away. If those are fine, then it might be worth pulling the thermostats again just to confirm they were installed in the correct orientation. I mean, you can't really be sure right? Better safe than sorry.

 

[DickerSon85]

I'm thinking something about the cooling system probably. Water pump that's bad, air in the system or a clogged hose? Yeah, the thermostat as well.

 

[Kangg]

When you put them back in the water, did you check if the raw water pumps are actually pulling in water? A failed impeller or blocked intake could cause that overheating even if water's coming out the props.