Had a first happen yesterday!!! I have a Yahama V-Max 250 series 2 it only had 210 hrs on it and number 6 cylinder blew!! It is an 2010 motor but I did everything your supposed to do to keep it in tip top shape the mechanic said it is the fuel we run today! Man if thats the case we're all in trouble!! It is crazy what they want to replace the head on the motor! Has anyone had this happen and what is the best thing to do? I think I could almost by another for what they want to fix this one!!! All suggestions appreciated!!!

For one run non-ethanol fuel if possible. If not run a fuel additive such as Bio-Bor, or the recommended stabilizer for the motor. I believe it is Ring Free. I run the same engine, same year model with over 300 hours on it. My mechanic said I should get 1500 hours before I have trouble and he is a very reputable mechanic in Southeast Texas and specializes in Yamaha's. I bring mine in 2 times a year and have them go through everything. The worst thing you can do with a motor is let is set without a gas treatment for a couple months in it and fire it up and run it. Not saying you did but I have a one on one relationship with my mechanic and the ethanol fuel will deteriorate real quick without an additive and develop water in the gas that will hurt the engine.

Yup, ethanol or lack of oil got ya. That's the pits! You can just rebuild it yourself with some basic tools like this guy did.
https://www.amazon.com/rebuilt-Outboard-...ilt+an+outboard

If you're not one of those tinkering types your only option is to repower it and pay someone else the extra money to do it for you. If you were closer I'd come give you a hand. You buy the beer

Good luck!

I personally think some mechanics just search for something to blame. I was in a shop the other day and overheard a mechanic try to explain to a couple why they lost a cylinder, started with ring free and they said they used it religiously, then another additive same answer then he started mumbling trying to think of something else. Your boat was made to handle ethanol fuel wasn�t it? Mine is too old, in fact all of my boats have been to old to be made to run on it but have never had an issue. Been using it for years from any gas station that I come across.

One person is anal about maintenance and blows a motor. Another never does maintenance and it runs forever. So many variables when it was assembled and parts that just went premature, I think it is just a [censored] shoot sometimes. Like you said if ethanol was the culprit then he should have hundreds of boats lined up waiting to be rebuilt.

I"m of the same thought at Bobby. I don't see how Ethanol is directly attributable to a cylinder to blowing. Engines are designed to run many more hours than what you got. To me, it didn't get the right amount of oil, or some mechanical tolerance was out of whack, or something clogged. I'd be afraid that if a root cause is not found, it will happen again. If you decide to do it, I'd spend some money to get an extended warranty, if it even exists.

In manufacturing, it's a distribution of variables. And tolerances are designed it so that a very small percentage are going to fail. To design for zero failures is prohibitively expensive. I'm thinking you unfortunately got the small percentage that statistically fail in the field.

ethanol fuel if used regularly shoudnt be a problem but in a boat it may sit four a couple of months it will start to break down . on fuel lines that have been on a boat for a long time will build up inside the line eventually causing a restriction. on motors like hpdi s an optis they use a lot less fuel an oil than a efi or carb motor so the fuel an oil that services the motor should be clean an fresh.