Attachment 63232here she is blown #2 getting her bored tomorrow crank was good. They'll be looking for the root of the problem tomorrow also.

Awww...that's just a flesh wound. Hit her with a few passes from a flat bastard file, a new set of rings and she'll be good as new;). You are lucky the piston didn't seize in the bore and bend a rod and crank or bust out the block. Good luck on the repair.

Ijust talked to repair shop #1 &#3 just honed and #2 .020" over bottom bearing on crank was busted but all in all it's better than I expected, by Monday or Tuesday of next week I should be in break in mode!:D:D

What was the cause?

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Carb to lean cause ring to fail on exhust side.

That is a symptom, not the root cause of the problem. What caused the carb to suddenly lean out? Not being a a$$, just trying to help you solve your problem. Unless you solve the problem, the symptoms will reoccur.
Danny

My mechanic is looking into oil system. I'm thinking I'm going to pull oil injection off and mix fuel. It may have had something to do with the freezing conditions but the wear that was there was brand new do he seems to think its something that failed all of a sudden and not over a period of usage. And I take all you guys comments seriously I appreciate you helping me Danny.

I have a Mega in my shop that looks exactly like your Yammie. Middle cylinder has aluminum galled on the walls over the exhaust port. This motor was operated in 5 degree weather with a frozen water system, it overheated. The plugs and the piston you show do not indicate a lean condition. A lean condition would turn the plug white and leave zero carbon on the piston. Usually a lean condition will gall aluminum on the intake side first. Overheating will gall aluminum from the exhaust side first since it is the hottest place in the cylinder.
The factory jets carbs for all conditions from 0-120 degrees, that's why most factory motors run pig rich. Carbs don't just suddenly lean out. Especially if it was running great just before it died. My guess would be overheating, frozen water pump impeller????? I would drop the lower unit and check the impeller. It may have been frozen and sheared the rubber impeller from the plastic hub. It will look normal, but try to spin the rubber portion while holding the driveshaft, if the rubber turns, change it out.
As for removing the oil injection GREAT IDEA. A pinhole in an oil line and you grenade a motor. Hand mixing is a 100% fix for that problem.
D

Frozen water did cross my mind a few times.

I really don't see a lean problem there. Frozen water system on your motor. You have most likely found the cause. Next time it gets cold, drain the motor's water system when you put the boat on the trailer:)
D
D

I have seen 40hp Mercs do this. The water pump impeller would spin on the hub. At idle and low speeds, it would pump great. At anything above 2500 rpm, no water. That was a factory defect in the impellers. Yours sounds like a frozen impeller due to low temps.
D

could be, I was out hunting Friday before last in all that sleet and freezing rain, Saturday I was back everything still frozen over let motor warm up a couple minutes then left but that afternoon on my way back motor sputtered on take off but I thought ole 2 stroke cough... Sunday I didn't make a mile and poof. Mechanic said whatever it is wasn't something pre existing it's something that had just happened, I just called and said change water pump also, being that these guys are only charging me parts at cost no labor I may as well.

Not that I am the all knowing guru of 2 strokes, but my diagnoses would be overheating which is also a symptom-not a cause, now you need to find the cause of overheating, check water pump. Certainly not a lean problem, no evidence points to lean burn. All evidence points to overheat.
D

Water pump on order, it may even be riginal pump in there so just change as precaution. Again thanks much for your suggestions!

You are most welcomed. Just trying to help:)
D

Danny you the man!

Matt where do you find free labor? We've all needed that a time or two.

Life long friend offered it.

Picking her up today had to bore .020" over on #2 and had #1&3 honed, went new with everything except crank and powerhead. I'll be putting some break in hours this weekend!

Glad to hear it's lined out!

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