Exhaust Water Backflow From Overcranking

[DBG8492]

So I've owned this boat for a few years.

She's got a Beta Marine 25.

Had an issue with a blocked fuel line that effectively ran her out of diesel.

During troubleshooting, I did a bit of cranking without her firing - or firing and running for a few seconds before shutting down.

Once I figured out there was a fuel flow issue, I tracked it back to something lodged in the pickup tube. Cleaned it out, drained the tank, inspected as best I could, replaced with new diesel.

From there, I turned on the electric fuel pump and ensured I bled the Racor, and then the main fuel filter - which the manual for the Beta says is the last place you need to bleed before starting.

Then I tried to start her by running the starter for ten-second intervals three times. No dice.

It was late so I stopped trying and decided to read and see if perhaps there was someplace else I needed to bleed before today.

In the course of that, I came across information that said if you "overcrank" a marine diesel with a wet exhaust, water can back up into the cylinders and now I'm a little concerned.

What do I need to take apart to confirm this hasn't happened? I do NOT want to hydro-lock this engine. She seems to turn over fine - no weird sounds. Nothing out of the ordinary except it won't start.

My first thought was to pull the top hose off the water muffler and see if it was full - but felt I should ask someone before I just go pulling things apart.

Thanks in advance for any assistance and sorry I didn't do a "newbie" thread introducing myself first. I'm under a bit of a time crunch because I'm trying to get underway within the next few days...

[Scubaseas]

If it turns over fine it's not hydro locked. Hydro lock is when you get water into the cylinder. If you can crank it over, it's not water locked. Best way to get rid of water in cylinders is take all the injectors out and crank it.

If cranking long times (more than 20 seconds) shut off the engine raw water intake. Just remember to turn it back on after the engine gets running.

Some water lift mufflers have a drain on the bottom if you want to remove excess water or to winterize the boat.

[DBG8492]

Thanks so much for the info!

I was hoping that was the answer and will likely drain the muffler just to be certain.

And yes, the plan moving forward was to crank it with the seacock closed and open it as soon as it fires and starts running.

[DBG8492]

FYI

Checked the muffler - it was about 1/3 full. Shut off seacock, turned on the fuel pump, heated up the glow plugs, and she fired on the first push of the key... Turned on the seacock, and we are letting her run for a while to confirm we're ready to get underway on Saturday.

Thanks again for the assist!