Starting mercruiser 350 after boat almost sinks

[redlinj]

The how and why doesn’t matter right now! The mercruiser 350 I/o took on water up to the spark arrester! Checked oil and it appeared good, then noticed water streaming out of the dip stick tube! Didn’t try starting the engine! Other than changing the oil several times, what else should I do! Your wisdom is always appreciated!

 

[Scott Danforth]

Well, your starter and alternator are going to be toast. I would get that motor running as soon as possible. You need to dry it out

 

[Chris1956]

If freshwater, take the starter and alternator off and when wifey isn't looking, put them in the oven at 250*F. Bake them for an hour or so to dry them. They can survive.

 

[redlinj]

Ok, didn’t think of the oven thing! As far as the motor, would turning the engine over with the plugs out be of any benefit? And how about the thunderbolt ignition?

 

[Chris1956]

The thunderbolt ignition should be potted and waterproof. The distributor (if you have one) needs to be dried out. Wiping it dry is probably fine.

Turning the motor over with the plugs out is a good idea, as it will blow out any water. Also, add some oil to the cylinders and turn it over to distribute it.

You must start saving this motor right now. Drop the keyboard and get to it.

I would first run the motor for 45 minutes and then pull the starter and alternator to bake 'em.

 

[Lou C]

And keep changing the oil and filter. Might take 3 times or more, but getting it good and hot is the main thing.
One year I had a cooling hose on the back side of the engine pop off and I had seawater up to the pulleys. I would up replacing the starter and alternator, but the rest of the electrical stuff was more or less fine. Thank goodness I had put on like 8 coats of corrosion x on the oil pan over the years!

 

[redlinj]

I can’t believe that I pumped 5 antifreeze jugs of water out of the engine before I got to any oil! Sure wish I had an electric pump! Removed the plugs and more water drained out of most cylinders. Plugs looked good, but wet! Should I dry them out and put em back in or just put new ones in now? It is physically painful to remove and replace them, but you all know that! Will refill with fresh oil/filter but what about the 4bbl carb? Draining the bowl and accelerator pump enough? Engine will be connected to another tank with “good “ gas! Will try and start and run for an extended time! Any and all comments welcome! Oh, and it is Lake Erie water!

 

[Scott Danforth]

FYI, the boat should have been running Saturday. You only have a few hours befor rust starts

Get new plugs, get new oil, get new filters run from a small fuel tank and get the motor running

 

[redlinj]

Yes, but what about the 4bbl carb! If the bowl is full of water, how do you get it out? Just keep pumping???

 

[Chris1956]

If no drain on the carb, pull it and dump it out. The clock is running....

 

[redlinj]

Yes, the clock was running! Finally got the engine started! Ran for 15 minutes, then shut it off and checked the oil: a bit milky, but I expected that ! Been running for an hour now and temp gauge shows 155/160F. Oil pressure 160! Shutting off now and will change oil and filter at least one more time!

 

[redlinj]

Update: first oil change as stated was really more of a dirty dark brownish! The 2nd oil change, after running for 30 minutes was quite clean, but will run her again tomorrow and change once more!

 

[Grub54891]

I'll put some seafoam in the oil and run it for a bit. Change it out and it help alot. I'll use cheap oil for the initial changes and then the correct oil for the last one.

 

[racerone]

The concept of getting a submerged motor running ASAP is not well understood.

 

[Scott Danforth]

The concept of getting a submerged motor running ASAP is not well understood.

agreed

 

[Lou C]

When I had water in a cyl & oil due to blown HGs back in Aug ‘16, what I did was run it, drain out water and change oil, repeat 4 times but made sure to drain water each time so it could not seep back into the motor oil.
I didn’t take the engine apart till the winter ‘16-‘17 but because I fogged the cyls so much after draining when I pulled the heads there was virtually no rust except in the combustion chamber part of the cyl heads. It is a pain but worth doing....