Mercury Sport jet 175 not running/water in cylinder

[SugarSandTango2003]

Hello everyone, posting a bit of a story in the hope of some help.

I have a 2003 sugar sand tano with the mercury sport jet 175 v6.

I was towing someone on an intertube and I had a significant (and fast) loss of power, and I was able to drive the boat back to the marina with the limited power until it stalled right near my slip. The boat initially cranked but wouldn't start. I have replaced the following parts:

Stator
trigger
voltage regulator
all spark plugs
fuel pump rebuild

The boat was sitting for about 2 weeks and was having trouble cranking when I went to start yesterday. I pulled all the plugs and turned the engine over by hand to find water in my bottom port cylinder (video attached below). After cranking the engine with plugs removed and getting out all the water, I started the boat and it fired up immediately (video attached). It ran briefly then slowly idled down and died. It wont restart after that short run, but cranks just fine and no water in cylinder after the 30 seconds of running. Compression test shows about 115 psi on all of the cylinders on the port side.

What should my next steps be/ what should I test/replace next?

Any help appreciated and also putting out a $25 prize to anyone who gives me advice that gets her running once again!!

boat2.mp4

drive.google.com

boat1.mp4

drive.google.com

 

[racerone]

If this motor had water inside on the bearings for 2 weeks you may have major rust damage on bearings.----Some will argue, but I think this unit needs to come apart for inspection.

 

[SugarSandTango2003]

If this motor had water inside on the bearings for 2 weeks you may have major rust damage on bearings.----Some will argue, but I think this unit needs to come apart for inspection.

Don't think the water has been in there for 2 weeks (I'm not 100%) but the boat was able to start briefly about a week ago.

 

[cyclops222]

The leak is getting bigger and worse. Running heat causes the leak to start. The engine does need a pull apart.

 

[Faztbullet]

Could have blown cylinder head O-ring but more likely divider plate gasket or hole burnt thru. I have to agree with Racer, as that much water out of cylinder there is internal rust problems.

 

[SugarSandTango2003]

Are there any tests I should run, I have seen people mention exhaust manifold and other things to test? I don't mind tearing down if that's what needs to happen, but rather not use the open it up and see method if not needed.

 

[cyclops222]

Sadly your engine is that damaged.

 

[Dukedog]

tha longer it sets (stays together) tha deeper any surface rust will get......
jmo.