Exhaust manifold not draining when probed with coat hanger?

[CurrentObsession]

1999 Sea Ray 290 DA with twin 5.7 freshwater cooled blocks and manifolds.

Tried to winterize today but starboard side exhaust manifold on starboard engine didn't drain any water when I pulled the blue plug out. I am perplexed as I have done this many times with various engines and always had water coming out. I spent several minutes with a stiff wire and nothing. I swear I am hitting solid metal with the end of the hanger, not dirt.

I am thinking I need to hook up muffs, get the engine running with the plug removed to see if internal water pressure forces out what ever the obstruction is?

Suggestions welcomed.

 

[QBhoy]

Hi

Depending on the circumstances and order you drain in...you won’t always get much water out here. If you really want to be sure...take the thin hose that attaches to the front of manifold and t stat off at t stat...take the plug or stubby blanking plug out the rear of manifold and blow through it from the hose end. If you feel air coming out the back...you’re good.

 

[Bt Doctur]

freshwater cooled blocks and manifolds.


Then the only thing to drain are the elbows have never seen a blue plug in an elbow

 

[CurrentObsession]

freshwater cooled blocks and manifolds.


Then the only thing to drain are the elbows have never seen a blue plug in an elbow

I've had 5 different GM engine boats and all of them had plastic blue drain plugs in the bottom of the exhaust manifolds.

 

[wingless]

1999 Sea Ray 290 DA with twin 5.7 freshwater cooled blocks and manifolds.

Tried to winterize today but starboard side exhaust manifold on starboard engine didn't drain any water when I pulled the blue plug out.

I've had 5 different GM engine boats and all of them had plastic blue drain plugs in the bottom of the exhaust manifolds.

The freshwater cooled manifold will not have a blue drain plug on the bottom of the exhaust manifold. A freshwater cooled exhaust will instead have an engine antifreeze hose w/o a drain connected at that location and the raw water will instead be plumbed up to the elbow.

It sounds like your freshwater cooled engine instead has raw water cooled exhaust.

Yes, it makes sense to operate the engine again, using muffs, to verify normal water flow out through both blue drain plugs prior to finalizing the winterization process.

 

[CurrentObsession]

My apologies, I have raw water cooled engines and exhaust. No antifreeze anywhere.

 

[alldodge]

Suggest remove the hose off the thermostat housing going to the manifold and connect a garden hose to it.