A cracked anything is usually caused by freezing. I've had something similar with and old OMC motor but they put burst plates in those old two stroke motors that could be replaced cheaply preventing engine damage. That happened to me 30 + years ago and ever since then I've stored my motor in the down position when I get my rig back in the shop so it can drain.. I've also learned with these Yamaha SHO's you need to raise and lower the motor more than once to get rid of the trapped water in the block. With mine when I get it bottomed out it will dump some water, I can raise it back up and let it down again and just about as much out of it a I did the first time.

What did you try as far as saving money?

This one has never been in temperatures low enough long enough to crack it. Plus I did an oil change a few months back and the oil was clear

Combustion chamber cleaning.

At first mechanic said he didn’t see anything wrong with motor, but engine oil looked like nothing he ever seen. He thought previous mechanic put something other than oil in it, but didn’t save a sample or the filter. Said there was no indications of water being present.

So they changed oil, ran for an hour or so, and then changed oil again. Put in new spark plugs.

Seemed to work for about a half day. I fished a tournament on Alan Henry and it didn’t smoke once. Around lunchtime I cranked up and ran from upper lake to dam area, when I went to stop I had a trail of smoke down the lake behind me.

So I brought it back to shop.

He felt block wasn’t cracked but I had something sticking from the “non” oil issue. So he suggested we conduct a combustion cleaning process. Basically run 6 gallons of fuel with 10x or more recommended loading of sea foam. Then change oil filter, and plugs.

Went back to Alan Henry. Under mechanics suggestion I ran it for about 30 mins at 2500 rpm’s and then stair stepped it up 500 rpm’s every 30 mins.

I would stop and restart periodically cause smoke was usually only obvious when starting.

I never saw smoke on starting until I ran it at 5000 rpms and smoke while running over 5500 rpms.

So I kept using the boat at 4500 rpms and below with sea foam for a few weeks. I thought it was working and running better. But each time I would attempt to increase rpms it would start burning oil.

Then one trip, even while running at 4500 rpms, my oil level went from good to setting off my low oil alarm.

Took it to another mechanic, that said it would likely be cheaper to replace head than to tear apart and pay for labor to diagnose the exact problem.

Got tired of not having a dependable outboard, so paid for the new power head.

Boat runs fine now, but with same exact prop on new power head I’ve lost about 5 mph. Used to be able to run 57-58 in my 22’ CC, now I run 52-53 on most days. Have gotten up to 55 a couple times with wind at my back.

Good Luck, it’s a sickening feeling for sure………..

I pretty much missed the whole spawn that year in my boat, and I absolutely hated fishing our club tournaments out the back seat, although I was thankful to have a buddy whom I could fish with.

Is this a common cylinder to lose? Does the head crack on this side? Is it the port or starboard side? Sorry I’m not familiar?

Sorry you're having issues with your Yamaha. That sucks badly enough when you are close to home much less far away from home on vacay.

A lot of the 2011 & 2012's had issues. I had one of the first 2011 Yam SHO's 250s that came to Texas on a new Legend. It was flawless. I had about 600 hours on it when I got a letter from Yamaha saying my motor serial number was in a series of motors that had some issues with the oil pump and that they were replacing the powerhead under warranty.

I took it to Fun N Sun a few weeks later and they replaced the powerhead at no charge.

Cracked head. $7,100. Don’t ask me how I know.

Replacing the power head hurt this poor boy. It had to be done though, I didn't know Yamaha quit sending just the power head to be replaced, now they send the entire upper, all new belts, injectors everything all assembled. New motor except for the lower unit.. I was offered 50 grand for the boat after the install tho!! Made me feel better anyway LOL.

These folks are the only ones I know of that are authorized to do Yamaha factory warranty rebuilds. Great folks to work with. If you do wind up with a major repair I would call them for a second opinion.

https://www.hydrotecmarine.com/

Everyone I’ve seen who has tried to rebuild there motors end up ordering a factory powerhead at some point down the road.

99 percent of our failures at work on Sho motors are rod bearings from gas getting past the rings on initial break in thinning the oil out. I’ve seen a lot of high hour Yamaha motors start to have value guide issues after 2k hours down in Florida with occasional cracked heads also

I'd sell everything that worked on the motor and go repower with new engine with warranty if you can find one it will be quick and the way I'm reading it that motor is 11 years old. Your starting that painful end of life slide on that engine and I would put it and myself outa that misery as quick as possible, next will be a lower, next will be a ????, then another?????...... it will go on and on.

Repower!

Does anyone know the correct method of narrowing down which side is cracked? I checked the spark plugs and they all look pretty clean.
I’ve read where you can pull the valve covers and connect garden hose to inspect for water coming through.
I’m just trying to narrow down which side it is.

Anyone performed this diagnosis?