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350 MPI Merc Not Starting

new2boats78

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"Boat is a 2001 Calabria Cal-A

"Boat is a 2001 Calabria Cal-Air Pro V
Engine is a Mercruiser 350 MPI

This past Sunday I decided to get one more day on the water after changing my oil and fuel filter.

Took off from the docks and had a 20 minute run out to where we board. Kept my eye on oil pressure and temp (it was 160ish), oil pressure was fine. During this run, everything ran fine, no alarms. Pretty normal.

We stop, turn off the motor. I suit up to board. Buddy starts the boat to pull out the slack in the 75 foot rope and the engine alarm goes off. He instantly shuts off the motor.

I get in the boat and turn on the power and watch the temp gauge is now at 240!

We wait for the motor to cool to give it another try. Temp starts to climb so we shut her off and get towed in. Now the motor wont even turn over. Just a loud CLUCK when i try to start it.

HELP!!!!!!!!! Thank you in advance for any light you can shine on this."
 
"unless you really overheated

"unless you really overheated that motor hard, i would be surprized if it's seized. See if the motor will roll over by hand. Use a 1/2 inch drive sock and wrench on the crank shaft nut. Hopefully it will turn over by hand.

Is it fresh water or sea water cooled? We'll go from here."
 
"David,

The boat has only r


"David,

The boat has only run in fresh water.

Should the motor turn over easily?

I did not run the motor when it was over heated. As soon as I saw the temp gauge rise I shut the motor off."
 
I would pull the spark plugs t

I would pull the spark plugs to see if it hydro-locked. Nothing was said about it running on after the key was turned off but I suspect that it did.
 
"Sorry for the ignorance gentl

"Sorry for the ignorance gentlemen but what is Hydro-Locked?

After trying the 2nd time after the motor was cooled way down, it didn't start after that. I plan to pull the plugs this week.

How bad is Hydro-Lock?"
 
Hydro- locked is when water en

Hydro- locked is when water enters a cylinder and keeps the piston from being able to reach the top of it's stroke. When this happens the water is compressed in the cylinder and the engine can't turn.

If you find water in one or more cylinder you have a leak between the water jacket and either the exhuast system or the intake.

Most times it's the exhuast manifold. Check and make sure no water has entered the oil system.(water in engine oil) Keep us updated.
 
"See Charli's post, but in

"See Charli's post, but in some cases, the motor runs on as I said and water can come into the cylinder(s) from the exhaust. Hopefully, it's nothing major."
 
"Update:

Charged both marin


"Update:

Charged both marine batteries over the past two days to make sure I have enough juice to turn over the motor.

I tried to start her up last night and she tried to turn over but I think she spun backwards a lil?

Am i screwed?
sad.gif
"
 
Did you pull the spark plugs b

Did you pull the spark plugs before trying to turn it over? If not remove the plugs and try it.

Let us know what you find.
 
Update!

Ok guys.

Pulled


Update!

Ok guys.

Pulled all my plugs and ALL 8 cylinders had water in them so I cranked over the motor to get the water out and a bunch came out.

Next I took some 25/40 oil and put a lil bit in each cylinder and turned over the motor to lube things up. Also did a compression check on the left bank and numbers looked gook.

Cleaned up the plugs and then put them back in.

She fired right up. No knocking or pinging. Ran smooth.

Going to put her in the water tomorrow to see if she will pull raw water in or over heat.

Suggestions? Reasons why all 8 got water? HELP!
 
"You need to check the compres

"You need to check the compression after running it. Putting oil in the cylinders pretty much guarantees a good reading.

The water probably got in when the motor rotated backward, like you said it did. When a motor runs on, it can rotate backward at the end, at the end of the run-on. It can get there through leaking gaskets but I think you'll find that it was from ruin-on."
 
Can I prevent a motor from run

Can I prevent a motor from running on after I turn it off? What actually causes that?

If it was leaking gaskets would I get all 8 cylinders?
 
"Let it cool down after a hard

"Let it cool down after a hard run before shutting it down. Use good gas and make sure it's not running lean. The 4.3L V6 has more problems with this than the V8 but if it did overheat, that can have an effect. Make sure your impeller is good and if it overheated because of that, don't run it until you replace it. Check your oil cooler for blockage. That can kill your cooling system and your motor.

One gasket leaking won't usually fill all 8 cylinders. If the exhaust manifold gaskets leak, it's usually one at a time."
 
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