Help. Hydro locked my 6.2mpi. 2001 sea ray 23’

Oldnbold

Seaman
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Jun 27, 2017
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I need advice as to what’s next. Today after a 10 minutes cruise, then a 3minute idle speed cruise, the temp alarm went off showing 220 on the gauge so I killed the engine. I popped the hatch and my IR temp gun read 160-185 on various parts of top of engine. Oil filter temp was 185. Elbows/ risers were 190. The thermostat housing showed 212 deg.
the water pump has 3hrs on it and ran fine all weekend.
I assumed debris obstruction in the lower unit so I jumped in, felt around but found nothing. Checked temps again with gun and Thermostat housing down to 185 while remainder of engine cooled down more.
upon attempting to spin engine with starter it immediately sounded like hydro locked. A few more attempts and I knew I needed a tow.
got home and pulled all the plugs. 6 of 8 plugs were wet. I spun the engine over blowing out the water then put a liberal amount of wd40 in the cylinders, blew that out, and will see what tomorrow brings.
Help! Any idea what the hell happened? The engine has 495 hrs Fresh water use but severe electrolysis on the bravo1. The water pump and t-stat have 3 hrs. I’ve owned the boat for 10 hrs.
 

achris

More fish than mountain goat
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May 19, 2004
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27,468
Pull the exhaust manifolds and elbows. Sounds like they are tell you they need replacing. At almost 20 years old, they've had a long life.

When was the last time they were pulled off and checked?

Chris........
 

alldodge

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This should not be an issue but just in case. Measure the distance from the water line to the top of the exhaust elbow, it should be at least 13 inches.

Also if you there were more folks on the boat during the cruise that weighted the boat and it was sitting lower
 

JoeRJGR

Petty Officer 3rd Class
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Jun 3, 2016
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How do you get severe electrolysis on an outdrive that has always been in fresh water?
 

Oldnbold

Seaman
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Jun 27, 2017
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Thx. To my knowledge, the exhaust has never been inspected. I can pull them but don’t know how to inspect them. What am I looking for?
 

Oldnbold

Seaman
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Jun 27, 2017
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Electrolysis?: my best guess was the PO kept boat in the water and an electric shore line was constantly hooked up.
 

alldodge

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If its always been in fresh water my guess would be the exhaust are fine. I have a set of 1994 in the shop which are in great shape that I took off maybe 5 years ago during repower. Checking would be good in any case just to rule it out.

If you have dry exhaust they can be pressure tested by just removing the elbow

Electrolysis would effect the drive but not the exhaust
 

indybleck

Petty Officer 2nd Class
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Sep 29, 2011
Messages
136
Sounds like blown head gasket, if you pull the exhaust elbows look down to the crossover and see if the flappers are plugging your exhaust. Check all your cooling lines, previous owner of my boat told me there are check valves and sometimes the balls get stuck and won't let water flow.
 

Oldnbold

Seaman
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Jun 27, 2017
Messages
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Electrolysis?: my best guess was the PO kept boat in the water and an electric shore line was constantly hooked up.
 

Oldnbold

Seaman
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Jun 27, 2017
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Update: plugs are back in and the boat started as normal. After 30+ mins of idling in the water sittingVary in boat lift my temps per the IR gun are: 150 ish all across top of engine . 155 oil filter. T-stat housing 172 at housing but temp sending unit and ecm temp sending 187. Exhaust manifold and risers and elbows : port side 210 while starboard 195. Raw water hose at tstat 98. The other 3 hoses vary from 150-165.
 

Oldnbold

Seaman
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Jun 27, 2017
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I’ve the port side riser and elbow removed from exhaust manifold and see no scale or blockage in manifold nor riser. This was the hotter of the 2.
I pulled the t-stat looking for obstructions. Nothing there

i guess next is to pull the hoses on the steering pump cooler looking for obstructions like impeller vanes?

FYI when I changed the sea water pump 3 hrs ago, there was a vane in the intake side of pump. The impeller installed was very pliable and no cracks. I changed anyway.
so...keep going looking for obstructions???
 

alldodge

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You are running in the water and not on a hose?

Pick up a piece of clear hose, clamps and doubled barbed fitting at the hardware store. Connect the clear hose between seawater pump and thermostat housing. Your looking for bubbles
 

Rick franchi

Recruit
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Jun 29, 2020
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Second generation alpha one exhaust bellows replacement necessary with small cracks... shifter cable bellows easiest way replacement
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Second generation alpha one exhaust bellows replacement necessary with small cracks... shifter cable bellows easiest way replacement

quit hijacking the thread. the OP has a 6.2, which would not be paired with an Alpha drive
 

Oldnbold

Seaman
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Jun 27, 2017
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Update. So taking advice about not enough volume, I pulled many of the hoses and back flushed them and saw nothing. I installed a new main water pump , but most importantly ( I think) without pulling the exhaust manifold off the port side, I fashioned an auger to auger the port where the water feeds into manifold at the bottom.
started the boat in the water and brought up to temp. The port exhaust (formerly the hotter of the 2 sides) is running 160-170 while the untouched starboard is running 200.
i think my smoking gun is blockage in the exhaust manifolds. I’ll auger out the starboard side tomorrow and keep a close watch.

I also found the exhaust flaps are MIA, so I’m guessing my hydro lock was caused by a quick engine shut down on a moving boat.
 

tank1949

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Apr 4, 2013
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Electrolysis?: my best guess was the PO kept boat in the water and an electric shore line was constantly hooked up.

Make sure heads aren't eaten through. My salt water MC hydro-ed after sea water ate through a thin metal passage in head. If fresh water hydro-ed motor, you may be able to just replace heads but I suspect total motor rebuild/replace will be more cost effective and mind ensuring. I have never heard (various forums) of any electrolysis like you have experience with a fresh water boat. BUT, I only do salt water boating. If it was me, I go ahead and pull that old motor and start tearing it down. You might find just a blown head gasket that allowed water into cylinders. You could pull heads with motor in boat. Replacing head gasket is easy.
 
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