***Weird motor question.....need opinions!

[rmk addict]

I am currently installing "the fix" on my 09 800 RMK. I thought it had seized last year riding down the trail, I heard a noise and the sled shut off, and then was hard to turn over. T stat was reading normal temps, and I had the scratchers down.

Upon tearing down the top end, I discovered the PTO side had classic Poo smeared all over it with typical vertical scoring, and uneven feeling piston and cylinder walls, low compression....you get the idea.

Here's where it gets weird; the crankcase on PTO side was full of black oil, pretty much up to the bottom fuel injector. The MAG side was completely clean, and the MAG piston was looking okay as well.

I talked to the mechanic at my local shop, and he had not seen this problem yet.

I'm trying to think what would cause all this oil to build up, where it has been coming from, and why it hasn't been used.

I haven't split the case yet, but the outside PTO bearing case seems discolored when compared to the other three. The other three are greenish/bronze, and this one is grey, without any hue.

Like many, I am stuck with this sled for a few more years, so Im trying to make it work. Thanx in advance for the help, and lmk if I need to post more info.

Addict

 

[diamonddave]

Can you post some pictures so we can see what you're talking about?

Are you saying that the PTO side of the crankcase seems to be full of oil (and not fuel or coolant mixed in) where as the Mag side isn't? The only thing that comes to mind is maybe one of your oil injectors is stuck open and allowing to much oil to go in. These are the little brass deals that plug into the cases on the motor. They have a one way valve in each of them. They don't normally fail open but I have seen it before.

Try to post up some pics if you can.

 

[rmk addict]

Yes Daimond, you hit the nail on the head. I don't believe there is any coolant or gas mixed in. The oil is black, doesn't have any white trace in it, and I couldn't smell any fuel in it.

I think you may be correct about the oi injector sticking open somehow....

I guess the oil in the case is black because it's been sitting in there while the motor is running?!

Mag side looks completely normal; clean and not full to the brim with used oil.

I blew it on the pics, I drained it yesterday without snapping any. D'oh.

 

[sled_guy]

If it was full when running a couple of things would happen.
1 - Hydro lock, which would then break a piston or bend a rod.
2 - Blow out the exhaust... does the pipe have oil in it?

I'm betting it leaked in there after you shut it down. Did you start it and limp it out after it stuck last year or tow it to the truck?

What oil do you use?

sled_guy

 

[rmk addict]

Sled_Guy, good insight.

I towed it to the truck, and then it sat most of the winter, while I rode my beater.

The pipe did not have oil in it. Y-pipe was pretty clean too.

It certainly could have leaked in there while it was sitting, but I feel like if it did, the oil wouldn't be as discolored from the original orange tint.

Im using VES Gold sadly.

Since the piston failure was on the same side, and the oil is discolored, it make me think that maybe there was a case of hydro lock?!

Great ideas so far, thanx!

 

[diamonddave]

The oil being black is probably due to the failure of the parts and overheating when the failure occured. I would also agree that it may have filled up the crankcase since the failure over the summer. I would be checking each injector close, maybe replacing them all. They aren't cheap though, it seems I paid close to $20 each last time I needed them.



I would definately be opening up the lower end. Check all the flat surfaces of the cases and monoblock just to make there isn't a base gasket not sealing. Knock down any high spots with a knive sharpening flat stone before you install the dowels.

 

[BB454]

Oil

Even with a dead hole, that stuff should have blown out of there while the engine was running. Kind of like one that was flooded. After you get a flooded one started, the excess gets pushed out the pipe. I would be more inclined to believe it's weepage from sitting.
If you are going to the trouble of installing the fix, I would have the crank gone through.

 

[theshadowrider]

Could be from running the engine with a dead cylinder with no compression. Fuel and oils puddles in the bottom then you parked it and as it sat the gas evaporated leaving oil left. Jut a thought.

 

[rmk addict]

Thanx guys, these are all great ideas.

I will be splitting my case an inspecting my crank and bearings, as well as all the oil injectors.

 

[WyoBoy1000]

i think its from sitting, if it was over oiling would be less of chance for scaring of the cylinder. Probably just picked up left over deposits of crap that was in there before the failure and changed the color, I would almost bet if you put a little on a piece of white paper it would still have the normal color tint to it.