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  1. #1
    hintonpaint's Avatar
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    crank case filled with oil 1996 SLT 780?

    I have a 1996 SLT 780. This ski hasn't been cranked in 3 years. The guy I got it from parked it one weekend under a tree in his back yard (yuk) and just left it there. The body looks like total crap, but the engine and engine bay looked perfect. I put a new battery in it and tried to see if it would turn over. It sounded funny so i quit after a second or two. I pulled the plugs to see what shape they were in and they were soaking in oil. I looked into the cylinders and they were also full of oil. I purged as much oil through the spark plug holes as I could but it just kept coming. I'm about 90% sure the crank case is full of oil, question is, how do I drain this oil? Any ideas why there is so much oil in this thing? My first thought is "bad oil pump"... i may just swap to a oil block off plate and run pre-mix as I just trust that more.

    Thanks for the help!


  2. #2
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    A couple of things you can do.

    1. on the exhaust side of the engine are 3 drain plugs. If you can access them, that's the best route.

    2. You can remove the carbs (highly recommend if it's been sitting for 3 years) and intake manifold. That will allow you to get a modified vacuum hose into the bottom of the crank.

    I highly doubt the oil pump is leaking. More likely that the previous owner winterized it, and put way too much oil down the cyls. (actually a good thing if it's been sitting for such a long time. It kept the crank from rusting by having it in there.

    I recommended the carb removal because the ski sat for so long. You should go through and rebuild or THOROUGHLY clean them.

    Not a bad idea to replace all the fuel hoses while your at it. They're 13 yrs old, and possibly dry, cracking, or deteriorating on the inside.

    Also clean/inspect the petcock for blockage.

    Since there's excessive oil in the crankcase, you'll want to remove the pulse hose and see if any is inside of it. If so, then remove the fuel pump and inspect it. You do not want gas/oil/water filling up the vacuum side of the diaphragm. You'll get no fuel pressure or weak pressure.

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome to the best place on the Internet for Polaris PWC support!

    Click here for Polaris Service Manuals, and other useful info.

    Since you tried cranking it while there was fluid inside the crankcase, you may have cracked one or more pistons. Oil/water doesn't compress, so with the spark plugs in place, the piston cannot rise, but the starter motor keeps trying.

    Also the fuel pump doesn't like having liquid forced down the pulse line. You should consider rebuilding or replacing that triple outlet fuel pump.

    The link above will also take you to the Mikuni carburetor rebuild guides. Those carb really should be cleaned and rebuilt to ensure they are not gummed up or clogged internally.

    It is important that the entire fuel system, from the fuel tank through the hoses and fuel selector, to the carbs themselves, be in 100% good working order. Any problem in the fuel system which reduces fuel delivery to the cylinders while riding can cause lean burn, where the pistons get so hot they have holes meted right through them.

    The Polaris oil injection pump is actually quite reliable. As long as the hoses are in good condition (I suggest installing new oil and fuel hoses), and the oil filter is replaced, it tends to just keep working. Of course, you do need to inspect the hoses, camps and control linkage periodically.

    The oil pump has a fail safe mode, whereby if the throttle linkage disconnects, the pump arm falls back to a 100% oil flow rate, protecting the engine.

    When the variable rate oil pump is working normally, you use about 1/2 the oil that you would with pre-mix. At low engine RPM, the oil pump reduces oil flow, since the engine doesn't need much oil. As WOT, the pump delivers about 40:1 oil flow, same as pre-mixing.

    Less smoke at idle, less oil consumption, and simpler refueling - no chance of someone forgetting to mix the oil correctly.
    Last edited by K447; 05-19-2009 at 11:31 PM.

  4. #4
    hintonpaint's Avatar
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    this was my brothers project and he will be out of town for a while now, however i wanter to say thanks for all the great info!

  5. #5

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    Pull the carbs like the guys have mentioned, as you will most definitly need to go through them (and entire fuel system). Once those are off, pull the reed cages (inspect them while your there).

    Now, go get a mity vac kit and use a little hose attached to it to stick into the cases and suck out as much fluid/oil as possible. You can shoot a little gas in if it is really bad to dilute the oil and help it flow easier.

    Their is the plugs on the bottom of cases but they are usually a complete pain in the @ss to get to and you run the risk of screwing up the threads. This is why I just go through the intake with suction.

    Spray a little fogging oil in the intake, button it all back up after you go through the carbs and you should be golden.

    Crank it over for a little bit before reinstalling plugs, then do a compression check before firing.


    Having the engine full of oil during long storage is a great thing wether intentional or not. If it wasnt intentional, it's the pump and just replace it or go premix like you mentioned.

    shouldn't be too big of a problem

  6. #6
    hintonpaint's Avatar
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    thanks redline, as soon as i get back on that project that is what i was going to do to a tee. the only thing different from my plan was to use denatured alcohol to wash the case out. i already have the block off plate in and i should be back on this one in about a week or so. i am currently working on my 03 fx-140, almost complete engine rebuild and a 98 gtx-di that was just dirty from salt water mess. i will keep you posted on my brothers polaris, thanks again for the input guys.

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