Mercuiser 3.0 Popped rear core plug

[Nstri68]

Hi folks, looking for some advice.
While on the water last weekend , I popped the rear core plug in my 3.0 mercruiser (found it in the bildge) Was able to get back to shore without too much drama, but now accessing the damage.
While running on muffs, the engine starts right up , no visible cracks, oil looks clean, but I see two issues. The obvious one is water is leaking out around the flywheel, and the 2nd is there is no water coming out of the exhaust ports around the bell housing, just exhaust.
Would the missing core plug Have anything to do With the system losing prime, not allowing water to make it though the exhaust , just dumping out the core plug hole? My first thought was the impeller was bad, but it seems to be good enough to pull enough water to leak out the core plug hole. Since the motor is coming out anyway I will replace the impeller, wondering if I should be looking for other problems or if something else would be causing no water to be draining out of the exhaust ports. Any help or Insight would be greatly appreciated thank you.

 

[dubs283]

Would the missing core plug Have anything to do With the system losing prime, not allowing water to make it though the exhaust , just dumping out the core plug hole?

yes

the cooling system isn't building enough pressure in the block to allow exit out the exhaust

once you have the plug installed it's in your best interest to pressure test the cooling system to check for additional leaks

 

[Bt Doctur]

my question is how you winterized it this past winter. Core plugs are pushed out from freeze damage

 

[Nstri68]

yes

the cooling system isn't building enough pressure in the block to allow exit out the exhaust

once you have the plug installed it's in your best interest to pressure test the cooling system to check for additional leaks

That is what I was thinking, I don't feel any pressure on the hose, but also scared to run for more than a few seconds if water is not circulating.

 

[Nstri68]

my question is how you winterized it this past winter. Core plugs are pushed out from freeze damage

Drained from both Plugs, filled block and exhaust side with Antifreeze. Flushed in spring. I was wondering about this as well but used the same process on my other boats with no problems. As well the boat has been run 10 to 11 times this season prior to this happening.