Can someone help explain hydrolocked 2019 SHO 225

[Kenny3Times]

Hoping someone can give me some ideas of what went wrong.

Went fishing last weekend and it was a very calm nice day on the water. Moved around a few fishing spots and the boat was very normal. Came up to what would be my last spot of the day, set down very normal and idled up to a ledge, shut the engine down and fished for 15-20mins. Decided to leave, went to start the motor and it sounded at first like the battery was weak, then a metal grinding. Took the hood off and the starter was grinding on the flywheel and wouldn’t crank it.

Got home, pulled the plugs (noticed the top plug on port and stbd side each looked wet), dropped the lower unit and the engine still wouldn’t turn. Couldn’t budge the flywheeel by hand.

Took the motor in and a Yamaha tech came to look at it. Said there was water in the intake plenum and in 3 of the combustion chambers. The starter motor bracket had broken as well. Also, the ECU showed the engine shut down at 2250 rpms, which I know can’t be right because I idled into my area and turned the motor off with the key.

Im wondering is there any explanation for the water getting in the intake? I’m very experienced in operating a bass boat and know how to properly come off plane. I put about 300+ hours per year on an outboard.

Any thoughts on what could have caused this would be greatly appreciated.

[yam911]

Hydrolock results when the propeller is turning in its normal forward (clock wise) direction but the motor is in reverse gear. The intake becomes the exhaust and the exhaust becomes the intake. Water is then sucked up into the exhaust and gets into the cylinders, and possible the intake of the motor.

Typical scenario is that a guy is smoking along at speed and sees something (a log maybe) right in front of him. He chops the throttle. But in doing so he accidentally shifts into reverse. Maybe but for a nanosecond. The lower unit goes into reverse gearing. The propeller keeps turning clockwise due to the force of the water flow. The power plant is now rotating backwards.

[printman71]

Hydrolock results when the propeller is turning in its normal forward (clock wise) direction but the motor is in reverse gear. The intake becomes the exhaust and the exhaust becomes the intake. Water is then sucked up into the exhaust and gets into the cylinders, and possible the intake of the motor.

Typical scenario is that a guy is smoking along at speed and sees something (a log maybe) right in front of him. He chops the throttle. But in doing so he accidentally shifts into reverse. Maybe but for a nanosecond. The lower unit goes into reverse gearing. The propeller keeps turning clockwise due to the force of the water flow. The power plant is now rotating backwards.

Sounds like a really good reason to have a hot foot.

[yam911]

Sounds like a really good reason to have a hot foot.

Except for those that drive while standing. Gonna be ruff on the throttle leg.

[Kenny3Times]

Hydrolock results when the propeller is turning in its normal forward (clock wise) direction but the motor is in reverse gear. The intake becomes the exhaust and the exhaust becomes the intake. Water is then sucked up into the exhaust and gets into the cylinders, and possible the intake of the motor.

Typical scenario is that a guy is smoking along at speed and sees something (a log maybe) right in front of him. He chops the throttle. But in doing so he accidentally shifts into reverse. Maybe but for a nanosecond. The lower unit goes into reverse gearing. The propeller keeps turning clockwise due to the force of the water flow. The power plant is now rotating backwards.

Nothing like this occurred. And the motor was fine when I turned it off, and was locked up when I went to start it again. So apparently it hydrolocked when it was off. Is that possible?

[yam911]

I can not think of anything that would hydrolock a motor that is not running. Other than on a twin powered boat. If one is running and the other is not, and the not running motor is down in the water, the motor is in gear, then hydrolock can happen. Not applicable to you of course.

Other than the motor being sabotaged by any jealous girl friends, wives, ex wives, ex girl friends.

Has the dealer mechanic spoken to Yamaha? I would be looking for some goodwill assistance from Yamaha.

[Snakebit95]

Blown head gasket? Cracked cylinder? Either will let water into the cylinder and could get pushed into the exhaust or intake.

[Kenny3Times]

Has the dealer mechanic spoken to Yamaha? I would be looking for some goodwill assistance from Yamaha.

Yes, they saw 1" deep of water in the intake plenum and determined it was hydrolocked. They don't cover hydrolock under warranty, so that was basically it from them.

[yam911]

Yes, they saw 1" deep of water in the intake plenum and determined it was hydrolocked. They don't cover hydrolock under warranty, so that was basically it from them.

I would call Yamaha and explain the situation. (866) 894-1626 Ask for some good will support. Be polite and nice. Yamaha may provide some parts with you paying the dealer for the labour. Try and strike a bargain.

I am at a loss as to how the motor can be running just fine, be turned off, and then suffer catastrophic damage upon start up. Takes a few seconds at start up for water to start to fill the block when it is running. From what I read, it appears the motor would not even crank.

Then there is the issue of the ECU showing the motor shutting down at 2250 RPM's. Was that at the time of the motors failure?

Good luck.

[Kenny3Times]

I am at a loss as to how the motor can be running just fine, be turned off, and then suffer catastrophic damage upon start up. Takes a few seconds at start up for water to start to fill the block when it is running. From what I read, it appears the motor would not even crank.

Then there is the issue of the ECU showing the motor shutting down at 2250 RPM's. Was that at the time of the motors failure?

Good luck.

That's correct, if it did crank it was just for a millisecond and then I heard the starter motor grinding.

When you ask "was that at the time of the motors failure" is there an actual date/time stamp that I could access?

Thanks for the tips and well wishes.

[yam911]

Using YDIS the dealer can extract data from the ECU. Whatever is telling the mechanic the motor was at 2250 RPM's when the motor shut down might show the total engine hours at that time. Which I am guessing would be the total time now.

There is so much more that I don't know than I do know.

Have you talked to your dealer about advocating for you with Yamaha USA?

[Wackyjig]

Yes, they saw 1" deep of water in the intake plenum and determined it was hydrolocked. They don't cover hydrolock under warranty, so that was basically it from them.

Find a different dealer to take it to. "it's hydrolocked so it's not warranty" is a bs answer. Something has failed whether it's a head gasket or a cracked block that allowed the water to get into the intake.

[yam911]

Very bizarre.

Motor running fine when shut down. Water drains from the power head. Won't crank when the key is next turned.

Without the motor running where could the water have come from? Cracked block or failed gasket. Water pump not turning and sending water up from down below.

Mystery.

[Snakebit95]

Very bizarre.

Motor running fine when shut down. Water drains from the power head. Won't crank when the key is next turned.

Without the motor running where could the water have come from? Cracked block or failed gasket. Water pump not turning and sending water up from down below.

Mystery.

Water drains from the powerhead and into a cylinder through a leaking head gasket or cracked head / block. Operator tries to start motor and piston squishes water and possibly bends connecting rod or damages piston. It does not take much water in a cylinder to hydrolock a cylinder considering the small clearance at TDC.

[yam911]

Water drains from the powerhead and into a cylinder through a leaking head gasket or cracked head / block. Operator tries to start motor and piston squishes water and possibly bends connecting rod or damages piston. It does not take much water in a cylinder to hydrolock a cylinder considering the small clearance at TDC.

Cracked heads and failed gaskets I understand. But the part about the motor running just fine at key off is not consistent with a gasket having failed or a head having cracked. Motor running fine at the time that there is water pressure within the heads and block.

And then at key off, when water pressure is minimal and falling to zero, water suddenly gets into three cylinders and the intake manifold?

I just am not understanding the situation.

[Riverrocket1]

Just gunna give a scenario..... combustion keeps water out of the cylinder while
running then once the motor is shut off the water in the block and heads could be allowed to seep in cyl. Now
ad far as intake having water in it is odd