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  1. #1

    2004 MSX 150 flipped... What to do?

    My in laws were on this ski for the first time and happened to flip it completely over for only about 30 seconds or so. Concerned because I have read about this problem with the Weber engine in these machines. I know the oil level was not over filled because I had just changed it the previous season (15 hours since change). The machine ran ok after flipped but noticed the oil was milky around the dipstick. After sitting for 30 minutes the ski would not start. After towing it to the dock I changed the oil the next day, drained by pulling the plugs and cleaned the interior, and cleaned the MAP sensors. It fired right up so I took it to the water to test it. When in the water it wouldn't start but when pulled out half way it fired right up. I put it back in and took it for a ride to test. It seemed to perform ok... 60 mpg and 7400 rpm. Not quite the top speed I was expecting but not too bad. What else do I need to do? I do not how to check the turbo? I do have two of these MSX150 with about 90 hours and have been happy with both. Any help would be appreciated?

  2. #2
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    Welcome to GH!

    Sorry to hear of the roll. They 150 doesn't take well to rolling in it's stock form. But at least you have a 2nd ski to swap parts to confirm good/bad stuff with.

    I'd start by reading up on the MSX 110/150 here: (the "capsized" thread in particular)

    Oil ingestion into the intake tract (airbox>turbo compressor>hose>intercooler>hose>hardpipe>hose>intake manifold) is the most common result of a rollover. In addition to this... water usually contaminates the oil (I suspect water out of exhaust/waterbox... back flooding into cylinder, then into the sump around the piston rings). This will make the oil milky/foamy... and that's bad too.

    You gotta take care of the oil first. Get it drained and flushed. Get it clean and milky/foam-free and set back to the correct level (see link above for proper oil level checking). With water contamination of the oil... this could take multiple oil changes. (Use cheaper Rotella T 15w-40 for these flushings... expensive Mobil 1 15w-50 full synthetic only for normal operation).

    Next you need to remove, inspect and thoroughly clean the entire intake tract if any oily gunk or excessive oil is detected. The intercooler is the worst... hard to remove. Hot soapy water, clean rinse and thorough dry for all parts. The intake manifold can be cleaned in place after removing the throttle body through the hole... as best you can.

    The 2 MAP sensors (one on hardpipe after the intercooler, other on forward side of intake manifold) are likely fouled and bad... if they got saturated with oil/gunk. They are both identical... only the hardpipe upper one uses the air-temp sensor function built into the MAP sensor. The intake MAP only uses the pressure part. I'd swap them off your good running ski to confirm if they are damaged.

    The O2 sensor also needs inspected. These are said to be damaged if while at operating temps are exposed to water... like a cold quench thing. A bad O2 will cause idling issues. You can unplug it and idle should smooth out... that's one way to test it. Or use a good one off your other ski.

    Further trouble is though... even if you get it all cleaned out, new MAPs, and good oil levels again... it's very possible and has been reported here multiple times that the ECU still has fouled/bad MAP sensor data stored in it's memory... and thus won't run right even though the problem has been fixed. Folks have reported a reflash of the ECU has brought it "back to life" and running normally again. I've also read where folks have just run the ski for some time to where the ECU relearns the proper MAP sensor readings in memory and starts running properly on it's own. There's been no hard data one way or the other done to test out this though...

    Weber Power sells an updated/upgraded oil tank with rollover side tank made by Weber for the engine. This will prevent the common rollover problems present in the stock, original design. These oil tank kits come with all the parts needed and are not too hard to install. I'd recommend them.

    Lastly... while your in there (or your mechanic if you can find one to work on these rare skis)... run a compression test on both cylinders. You want to see 130psi+ in each... or there could be troubles with your nikasil plating or "cooked" piston rings.

    Let us know what you find.

    Last edited by ripcuda; 08-12-2014 at 03:35 PM. Reason: forgot...

  3. #3
    Ok... I have changed the oil three times and it looks as though it will need at least one more change. Wal-mart sells the Mobile 15w-50... $22 for 5 quarts so that is not as bad as I thought. I also replaced the oil filter because my ski has 90 hours and it was due anyhow. When removing some of the hoses I found water in the big cylindrical tank towards the back (I think this is the heat exchanger) and removed and drained that water... just water though and no oil whatsoever. I also removed the hose from the intercooler and did not see any signs of water or oil contamination. So I did not mess with this. I also removed the MAP sensors and cleaned these.

    I ran the ski for a few minutes in the water, but it would not start when in the water. If I lifted up on the ski it would start fine. Still not running great and the starting part baffles me.

    I'm not a mechanic and do not know what to do from here. My plan is to change the oil a few more times until free of water and then run the ski to see what happens. Any suggestions would also be helpful and very much appreciated. Is there anyone in Montana that works on these skis? I have checked with the local Polaris dealer in Billings and no luck. Thank you for your time!


  4. #4
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    Hi Hob,
    That big cylindrical tank... was it on the opposite side from the battery? Did the turbo exhaust feed into it? If so... that's the waterbox (sorta like a muffler)... it's going to have water in it... no worries.

    The heat exchanger is a large, heavy, round cylinder shaped thing under the intake manifold on the battery/right side. It's mounted in a bracket to the underside of the intake manifold. A pain to remove.

    Have you done a compression test on the engine yet? This is very important to do on these MSX 110 and 150's. These engines have a number of known issues... and failing compression (usually due to Nicasil plating failure in the cylinder) is a big one. Buy a compression tester ($30?). Make sure your battery is fresh and fully charged. Pull the spark plugs (both) and insert the compression tester into one of the plug holes. Crank the starter (won't start obviously) while squeezing the throttle until the compression tester gauge stops rising. Read number, write it down. Now repeat with other cylinder. Then do them both again... and average your numbers. Report back the #s you get.

    A low compression ski will have a hard time starting in the water. If you lift/tip the left side... exposing the exhaust outlet... they'll usually start right up.

    I'd do this before you change the oil again. If compression is shot... no sense wasting oil.


    P.S. I'm pretty good at fixing these MSX 150's... bring your ski to Spokane, WA.

  5. #5
    I should have the compression test done by the weekend... ordered a kit from Amazon. Thanks for your help and you might see me in the next year in Spokane if the compression is good and I can't figure this our!

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