COOLING - Overheating Mercruiser

[aboynton]

Hi everyone,<br /><br />I have an overheating problem with my Mercruiser 233 (1976). After hastily preparing for a trip to the lake, I decided to fire up the engine before I left for the lake to make sure it ran. Forgot to turn on the water hose to the outdrive. Went out to the lake, noticed my temp gauge was pegged. Limped back to the dock.<br /><br />In retrospect, I remembered I didn't turn on the water. Checked the stern drive water pump and discovered I had SHREDDED my impeller.<br /><br />Replaced the entire stern drive water pump.<br /><br />After this, I turn on the engine and find that I now have water to the engine from the stern drive and also hot water spitting out of the exhaust.<br /><br />It approaches operating temperature and then continues to climb to 220 and peg again.<br /><br />What am I missing? What sort of damage did I do to the engine? What further tests should I run to get to the bottom of this?<br /><br />Thank you in advance for your advice.<br /><br />Adam

 

[labzman3]

Re: COOLING - Overheating Mercruiser

If that was a automobile,,my first suspicion would be a faulty thermoststat,, can you remove it and try running it for a little while to see if your temp drops ?? I'd even go so far as to catch some exhuast water,, and check the temp with a cheap meat thermometer,,might show that you have a bad gauge or sending unit,,, just my 2 cents

 

[Bondo]

Re: COOLING - Overheating Mercruiser

Did you Find,+ Remove, Every Single Little Piece of your "SHREDDED impeller" ??????????????<br /><br />If Not,<br />The 1 Piece you Missed is Stuck, SomeWhere between the waterpump,+ the T-stat.......<br />And is Restricting the Flow of Water...........<br /><br />You'll have to go Back where you Just came from,+ Back-Flush the System............<br /><br />Probably Hung-up on the P/S Cooler, If you have 1.........

 

[rodbolt]

Re: COOLING - Overheating Mercruiser

does the engine have closed cooling and or any power steering or oil coolers?