This is a oil pump malfunction no? Pic inside..

[Fenderjack]

OK so I just pulled the engine out of my ski today. I noticed the piston that went bye-bye the cylinder hole in the block is dry as a bone. The crank journals are dry as a bone as well. If you look at the picture you can see the difference in color on the dry cylinder and the cylinders that's wet.. I know some of you all said it was from a heat or gas/carb issue, but why would there not be any oil at all in that cylinder area in the crank ? regardless on this go around the only Jackson will be deleted but to me that seems like it is a oil issue that caused the cylinder to break

[K447]

If the crank or connecting rod bearing(s) develops high friction as it begins to die it generates a LOT of heat. That heat can kill off the normal oily film and accelerate the bearing failure, which creates more friction and more heat, and so on. Then the engine seizes, stops running, and cools down. No oil film left behind.



This is crank is from my own Virage TXi 1200 engine. The PTO connecting rod bearing failed, also punching a hole through the bottom of the crankcase. There was no oil film in the PTO section of the crankcase, it looked dry and cooked, yet the other two cylinders were still oily and looked very good.

[CrazyA]

Correct. Not to mention in your case, as the piston was melting away yet still running, you had fire entering your crankcase. You can burn away lubrication with too big a ring end gap or worn out rings let alone a piece of piston top missing. I just looked at your other pictures again and if this cylinder didn't let go, the center would have soon. Lean, lean, lean. Your PTO piston and head show foreign debri damage as well. You'll need a rebuilt crank I'm afraid.

[Mr. GP1800]

You do not have an oiling problem. When you burn up a cylinder like that it will ALWAYS look dry. Rebuild your motor with good quality parts and you will have years of fun on that ski.

[Fenderjack]

Yes I believe I will keep the oil pump, I am possibly going to make it run to a OP switch so that if it drops pressure it will shut the engine down, rather then a buzzer..

[Mr. GP1800]

There is no oil pressure. The pump is gravity fed and the lines have only a few psi pressure in them at most.

[Fenderjack]

Well scratch that idea.. Hahaha