What lunched this piston?

[MPower]

Ski was fouling plugs and then this happened.....

If you look closely you will see those metal fragments have a brass color. Damage is on the mag cylinder. Last picture is the PTO cylinder and if you look close you can see some small pieces of metal around the edge of the piston.

 

[Shortrun]

how do the crank bearings feel?

 

[MPower]

Haven't been able to dig any further yet. But once she died and tried to restart she was squealing like a pig. I
My suspicion is crank and rotary gear as well. How would those metal pieces make it from the crank to top of piston?

 

[soccerdad]

Everything in the bottom end can come up through the transfer ports to the top end. They just come up with the fuel and air.

 

[Shortrun]

Haven't been able to dig any further yet. But once she died and tried to restart she was squealing like a pig. I
My suspicion is crank and rotary gear as well. How would those metal pieces make it from the crank to top of piston?

Yup everything gets sucked up. Bearings and all. I was wondering if the brass colored is the connecting rod. The roller bearings at the crankshaft are much harder and do a lot more damage to the head than I see in yours.

 

[MPower]

I am about to finally pull this motor out so I can drop another one in.

Anybody have any other guesses on what the failure was? I'll post some pics once I get her apart.

 

[mikidymac]

If it is acutally copper then the only place it can come from are the thrust washers on the connecting rod big end.

 

[RodInEscondido]

Maybe it is just the pictures, but it kinda looks like some water got ingested and sat inside the engine ... just a wild guess.

I would recommend going thru the fuel and oil systems before taking a chance on a new engine.

Just saying ...

 

[MPower]

Alright guys, Suke and I got the motor out tonight and pulled the cylinders.

To remind those that don't know, when I found this ski the motor was frozen from the pistons being rusted to the cylinders, there was sand down in the crank case. It was rough. I pulled the cylinders honed them. Couldn't split the cases because the bolts were seized, but i was able to do a kerosene pressure wash and clean it out pretty well. Reassembled everything and have been running pre-mix ever since, which was about 6 years ago.

The damaged piston has a ton of back and forth play on the crankshaft and one of the thrust washers is destroyed. See pics below. What causes this sort of failure? Is it anything other than a motor with 200 hours that already had a questionable past?

 

[racerxxx]

I've seen it before and have found nothing to stand out, if on an engine without a sketchy past.

 

[mikidymac]

Well sand and probably some rust down in the crank it was a time bomb. Just be glad you got some time out of it. The bearings finally got enough play to start taking out the thrust washer and it was down hill from there.

 

[MPower]

She lives again!!!!

https://instagram.com/p/BULGuMChn3n/