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  1. #1

    Big issues with2010 RXT X is driving me nuts..!!!

    Hey guys i have a 2010 RXT X in my shop now that is giving me fits, to start out with some history: First season it worked perfektly besides the hose on the supercharger blew off and the ski was parked for winter with 25 hours on it.
    I sold it the next spring and after a while the guy who bought is started to complain it was not getting the RPM and speed it was supposed to, i tested it myself and it would run 7600-7800rpm and top speed would be around 66mph, rpm and top speed before was 8050 and about 70mph.
    I checked slip on the supercharger and pressure tested the intercooler and hoses and everything checked out fine, the impeller and wear ring also checked out.

    The hull was not very smooth because the owner would let the ski sit in the ocean for some time so i got it cleaned so it was nice and smooth and i picked up 3 mph on the top speed but the rpm was still down a couple of hundred but since i could not find anything wrong at the time the owner was told what i had done and i could not find an issue.

    He called me back after a little while and told me he still could not get the speed i was getting and it was getting slower but since i knew he would let it sit in the water i belived it was the hull getting rough again. Right after that the season ended here and i forgot about it until he called me this spring and told me had gotten a check engine light and he could not get past 6500 rpm.

    The code said there was an issue with the intake pressure sensor so i checked the supercharger and it had lost one of the friction shims, the ski now had 56 hours on it. I thought well at least we have found the issue with the missing rpms and speed thinking i had gotten a false reading when i checked the slip last year so i pulled the engine and replace all bearings on the crank, flushed the bottom pan and put in new oil pumps with pto housing and all and also rebuilt the supercharger with the newest parts.

    I got i back together and took it for a test run and i was still just getting 7600-7800 rpms and top speed was 66mph and on top of that when letting of the throttle from a full throttle run sometimes the oil light would come on for a second.

    I was thinking i would need to check the cam timing because of the missing rpms and put a pressure gauge on to check the oil pressure but the owner called and said he needed it that weekend so i told him what was going on but he said he would just take it back to me after the weekend.
    Friday night he called me he got to ride it half a mile when it suddenly stopped and he got a cam sensor code on it, because of all the issues he had with it i offered him a very nice trade in on a newer ski i had and he took the deal.
    I now started to look into the engine and as i suspected the cam chain had broken but what took me by surprice was that when i removed the spark plugs there was water in the front sylinder.
    I pulled the engine and did a leak test and on the front sylinder the exhaust valves was leaking so i pulled the head and both valves are bent and i can see the piston have hit both intake and exhaust valves.
    I pulled the pto cover and and put the front sylinder at tdc and the markings on the crank and balancer shaft is lining up perfectly so the gear has not spun on the crank.

    I have now 2 issues i dont have an answer to, 1 the missing rpms and second how did water get into the engine?
    I checked the exhaust manifold for leaks but it seems fine, i have not tested the intercooler yet but last year it was fine.
    I have been working on skis for the last 3 years and i have learned a lot but this one is really fighting me so all help is appreciated.!!!

    Regards from Norway

  2. #2
    Chelle's Avatar
    Join Date
    Oct 2008
    I had maybe the same problem, it was also a ski who was sitting in the water.


  3. #3
    Yes im going to test the intercooler again but what makes me think it is not the intercooler is that there are no signs of water ingestion on the other 2 cylinders.
    But after thinking about it i have a theory on how there got water in the front cylinder, when the engine stopped the ski was going close to 60 mph and doing 7000+ rpm.
    The timing chain snapped and the piston hit the valves bending those on the exhaust side leaving them open at the same time the impeller was still spinning from the ski going foreward filling the exhaust with water.

    Am i on to something here?

  4. #4
    Antiguan FZR's Avatar
    Join Date
    Jan 2007
    Antigua Caribbean
    I think you went beyond to help this guy, is he a great friend?? I would have walked after seeing barnacles!

    He probably towed the ski without pinching the water line and filled the exhaust then cylinder.

    Who leaves a ski in the water that long??

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