piston broke

[hutche]

evening all just need an answer about my brothers motor witch has a plate with serial numbers 708eto 6h3 L 469977,what year is it?but the big problem is as the attached picture shows a part of the top cylinder has parted ways,is it just a matter of replacing the piston or much more,he was quoted $3000 to fix it by the same scum who sold it to him as fully reconditioned,lasted a season with trouble from the start,worth the fix or buy again? appreciate the info

 

[hutche]

Re: piston broke

forgot to say its a 70 hp yamaha

 

[robert graham]

Re: piston broke

Maybe carbon stuck piston rings which snagged in port and broke off chunk. Can you crank engine over by hand so you can inspect cylinder walls for damage? If cylinders are O.K., maybe just replace pistons and rings? $3000 seems like a lot of money to sink in the motor, especially for the same "scum" who screwed you in the first place. maybe find a good used one for that?

 

[99yam40]

Re: piston broke

You need to find out what all is damaged and how/why it happened to make any type of guess.
We can not see much from here.
did it push something like a rod through the cylinder wall because of oil issue and ruin the crank too or did it just melt piston due to lean fuel/air mix because of plugged jets.
guy that sold the motor cannot control what type of fuel you put in it and how it is maintained

 

[pine island fred]

Re: piston broke

That seems like a lot of money. Is a bit of labor involved as those motors have one piece connecting rods. The connecting rod has no end cap that can be taken apart so all the pistons have to be removed with the crankshaft in order to get to the wrist pin. If it were my motor, I would put the 3K towards a different motor. Why was it FULLY RECONDITIONED in the first place? regards FRED