Oil in number 2 cylinder 96 xp

[Bcbackroader]

Hey all, I can't figure out why number 2 is pumping oil. First a little background. I bought the 96 xp800 last spring in running condition, but soon discovered both cylinders were freeze cracked. I pulled the cylinders and took them to a welding shop and had them welded up. Since there was very little cylinder and piston wear visible I honed the cylinders and reinstalled the Pistons with new rings and we were off to the races for the summer! Late last fall it became hard to start as it was turning over slowly and I determined the starter was tired so I replaced it along with the solenoid. Used the ski again without any problems, then the next time I took it out it was leaving an oil slick behind me. I put it back on the the trailer and looked at it a few days later and the bilge was full of oil. Then it wouldn't turn over, and I determined it was hydro locking from oil in number two. I turned it over with a rag over the spark plug hole and it puked out a lot of pure oil, not mixed with gas because I couldn't smell gas on the rag. I felt around the lines and connections and couldn't see where the oil was coming from that is in the bilge. I'm stumped, anyone have any ideas? Thanks

 

[Coastiejoe]

I think you have two issues. A leaking oil tank either at the lower grommet and or the seam itself. Both are VERY common. This would explain the oil in the hull.

The other issue is likely a bad crank seal. When it sits for a while the oil seeps past the seal and into the cylinders. Seal is cheap but it is a pretty major fix. The engine has to be pulled and almost always it needs a new crank.

What most do is, install a shut off valve on the oil supply line and turn it off while it is being stored between rides..

 

[Bcbackroader]

Thanks for the swift reply, Joe. There is no oil at the lower grommet, that's easy to reach. There is nothing that would point to the tank either, as all the mess lies right below the engine, but I will look again with that in mind. How does oil get from the crank seal above the Pistons? I'm trying to visualize the path the oil would have to take to wind up in the combustion chamber

 

[Coastiejoe]

It just does. LOL. I've not had the engine open to give an accurate answer. But it happens all the time. [MENTION=31048]LouDoo[/MENTION] can help with the details. If you have a 2-piece tank the seems fail all the time. There is a 1-piece tank replacement. But if your tank and grommet are dry, then you need to start looking at the lines and fittings.


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[Bcbackroader]

Could the oil be getting past the crank seal to the bilge? I have traced all the lines that I can reach by hand and they are dry. I'm going to have to start taking things off ( exhaust and air filter) to reach the rest of the lines. I'll take a better look tomorrow and report back thanks

 

[racerxxx]

The oil will leak past the crank seal and pool in the bottom of the case. When you turn the engine over the natural draw will pull the oil into the cylinder.

Check the little oil injection lines that they are not split. They should be replace if you haven't done so yet. The oil pump will need to be bleed after changing. You could also check the the oil pump isn't leaking. I've seen a few instances where the inlet fitting is loose, it shouldn't be since its pressed in. How much oil is in the bilge? Post a pic if you can.

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[68ragtop]

On the RV engines like you have in your XP there is a center section of the crank that is submersed in oil from your oil tank. Its under a little gravity pressure because the oil tank is located higher than the crankcase. when the seals start to leak, the oil flows into the sides of the case where the fuel mixture comes in. by design, whatever is in this area will go up into the cylinders. when its a small amount, you'll normally just notice a very Smokey first start up after the ski has been sitting for months, weeks, sometimes days if its leaking bad. Pretty harmless until it becomes so much the engine is hydro locking from the oil. The shut off works well because its like holding your thumb on the end of a water filled straw. (if that makes sense)

But, it sounds like yours might be leaking pretty bad. The oil injection system (check valves) could be the culprit too, but normally won't leak that much in a short time. Using a hose pinchers, you could probably rule out where the problem is.

here's a 2-stroke basics video. Except your engine has an RV valve instead of the reeds you can see.

Sorry about the Yamaha part, it was the first thing I found.....

https://www.youtube.com/watch?v=P-WYdrRKQvs

 

[68ragtop]

Sorry Racer, didn't see your post until I made one.

 

[Strizzo]

if the rotary valve on the #2 cylinder was open when it was parked, the oil could have filled the cylinder and run out of the carb i guess.

the reason the oil goes from the crankcase to the cylinders is because of the way 2-stroke engines work. air is drawn through the crankcase and as the piston goes down it pressurizes the crankcase and pushes the mixture up through the transfer ports into the cylinder. when there's oil in there, that goes into the cylinder.

 

[Bcbackroader]

Thanks very much for your replies, that sheds a lot of light on the situation. Can anyone recommend a valve for the oil supply line? Just a small ball valve perhaps?

 

[mikidymac]

You should try to determine how much oil it is leaking before installing the shutoff valve. If it fills up after a few weeks then the shutoff valve will buy you some time. IF the seal is leaking enough to fill it up in a day or two they you have no choice but to get a rebuilt crank.

 

[Bcbackroader]

 

[Bcbackroader]

as you can see everything looks pretty clean. I blotted up the spilled oil in the bilge yesterday but there was probably 250 ml in the bilge. Yesterday I pumped the oil out of the cylinder and fired the machine up and it smoked like a bastard. Today it started normally and didn't smoke much more than usual on a cold start so the seal can't be leaking that bad. Note the oil feed line is clean at the connection as is the #2 injector line. Injector lines remain soft and pliable so I don't really see a need to change them at the point. (Maybe they have been changed?)

 

[mikidymac]

At this point I wouldn't be too concerned with the oil in the engine after sitting all winter. Just keep an eye on it and see if it gets worse.

 

[Bcbackroader]

Ya I'm inclined to agree with you but my primary concern is the oil getting into the bilge as my pumps pump it out into the lake, that's not cool. I'm going to stick some absorbent pads under the engine and try to figure out where it's coming from. If anyone has any other ideas I would love to hear them!

 

[Bcbackroader]

Just out of curiosity, and looking forward does anyone know if you can re and re the crank without separating the jugs from the upper case half?

 

[mikidymac]

Nope, there is no way to disconnect the pistons from the rods without taking the cylinders off first.