Yamaha F225 Cracked Block w/pics

[jjsheehan6]

I purchased a boat last year that has a ‘03 F225 on it. It had 1430 hours on it when I bought it. Ran great, scoped for exhaust corrosion, and all cylinder compression was 190. I did not do a leak down test. My plan was to ride the motor out for a few years than repower. I knew the risks with corrosion ahead of time.

I started to notice oil on my transom well when the motor was up. After inspection I found a hairline crack on the block. The oil was slowly oozing out. The motor actually never lost much oil on the dipstick at all. There was never any performance differences with the motor. Since I’m inshore and always in sight of land, and a BOATUS member I decided to run it and monitor it. After 100 hours the oil lose is nominal. However it still does ooz slowly.

Could this crack be on the low pressure side? (Take it easy on me, I’m not a mechanic).
Is there anything I can do to buy a little bit more time with the motor?
Any intel or advice is greatly appreciated.

Disclaimer: I know the correct answer is to replace it. That is my plan. I just want to hear some thoughts on how it cracked and how much longer I have, and any ways to slow down the hemorrhaging. For all I know this was cracked before I purchased it, if that is possible.

[boscoe99]

I suspect that if the crack was on the pressure side there would be more oil flowing out. Hopefully, it is not on the pressurized side. Monitor the crack while the engine is idling to see if you can see oil flow.

On a 17 year old motor I would do what I could to stop the leak. Maybe strip the paint from the crack surface and then using something to open the crack up a tad. Something like a dremel tool with a V shaped bit. I would clean the crack as best that I could and then wipe it with a solvent to remove all residual oil. I would then use something like JB Weld for aluminum to seal the crack. In copious amounts.

Then monitor the crack and the oil level over time to make sure that no more oil is being lost.

[fairdeal]

this is the crack here?




Bizarre - and annoying.

But from what you've described - if it was my engine - I wouldn't bother messing with it.

Of course, as Boscoe suggests, carefully monitor it, and oil level.

[jjsheehan6]

Yes that is the crack. It goes just a little longer than that. There is no oil coming out at idle or even under load. Based on oil found after and that spot being a little oil soaked there is some but nothing visible to the eye. Appreciate you guys chiming in.