Overheating on 350 Mag engine

dhopplesr

I've experience overheating one of my engines only after getting up on plane. I could run all day at 8-9 mph and temp would read 175 where should always be. After extensive troubleshooting, we found the "ballcock valve" under each side of the manifolds were rusted and clogged.  This is a FYI so no one else spends the amount of money I did troubleshooting this nightmare problem!!
 

Black_Diamond

Why is there a valve there?  No such thing on mine. 

Cableguy Greg

Have you changed the impeller on the sea water pump? If you haven't, that would be the biggest reason that the engine would overheat while on plane.

dhopplesr

Sorry guys, I should not call it a ballcock valve, it's actually a 3 way check ball component. Mine was clogged up not allowing water to pass thru. There are two on each engine (350 mag). Very easy to access. $65.00 for each one. These little guys should be checked or at least replaced every 5 years.

Black_Diamond

Items 7-10 on this?

http://www.mercruiserparts.com/bam/subassembly/31747/7585/180

dhopplesr

Yes...I am surprised my mechanic didn't really know about this. I actually replaced the ones on the port engine also and they were ready to clog up.

rasbury

To many places to have problems...