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  1. #1

    Seadoo HX engine issues - Rotary valve or crankcase seals?

    Long story short, I recently came into possession of a '97 Seadoo HX. The previous owner had a work order from a mechanic he had work on the ski. In that work order, it said the mechanic found the crankcase full of 2 stroke oil, among a couple other carb issues. He fixed the carb issues and drained the oil from the engine.

    After that, the work order stops. Word of mouth from the seller of the ski is that the mechanic put the ski in the water and it ran for "awhile", before dying. After dying, apparently he couldn't get it to start again. Word is that the mechanic then got fed up with working on it, and recommended a rotary valve gear replacement from some other mechanic and charged the owner at the time something like $650 for the work already done.

    When we got the ski home, I managed to get it to start on the trailer using a bit of starter fluid. After that point, the ski would start and stop by the button without issue, but it was blowing a lot of smoke out the exhaust, enough to make me think it is burning an unusual amount of oil.

    I have a few questions now.

    If the rotary valve gear were really bad, would the ski run at all? I think the mechanic had no idea what he was doing and just pulled something out of his ass to get the guy out of his store. Evidence to this is that he supposedly cleaned the carbs, but didn't bother to replace all the old tempo fuel lines in the ski. Many of the forum members here know more than I do though, so I thought I would check. Could there still be a problem with the rotary valve?

    I've done some research about the crankcase being full of oil, and what I have read tells me there is a seal between the rotary valve cavity and the crankcase, and that seal often goes bad which allows oil to enter the crankcase. If that is what is happening here, then is it alright to run the ski for the rest of the season this way before pulling the motor to fix it, or is there other danger of damage to the ski other than running a bit of extra oil?

    The ski was actually purchased by a buddy of mine. I want to recommend we put the ski in the water now that it starts and runs on the trailer and try it, but I don't want to do any damage to the ski if putting a load on the engine is going to have any effect I'm unaware of. What do you guys think?

    Thanks much, this forum has already been so very helpful by way of search function and a couple other issues I've had. I have no doubt someone here will have the answers I need.

  2. #2
    flyin' the friendly skies airbornexp's Avatar
    Join Date
    Aug 2007
    Mahomet, Il. USA
    Betting on crank seals but you aren't going to know for sure till you pull the motor and take it apart. I wouldn't run it. It's dumping too much oil into the system and it's going to smoke like uncle bucks caddy. Besides with the seals jacked up, you are using twice the amount of oil. When you stop it will fill the crank case and it won't start again till it's drained.

  3. #3
    Thanks for the recommendation.

    I've seen some posts which say that if you replace those seals you also need to replace the crank itself. Is that true? We don't mind spending time on the project, but I know my buddy will be pretty hesitant to spend the extra $450. This ski was basically free for him, so he'd like to get it running if it can be cheap and might not mess with it otherwise.

    I got the price from here: http://partsfinder.onlinemicrofiche....HAFT---PISTONS part 290887862 please let me know if I'm looking at the wrong thing, I personally haven't dug that far into an engine before. Don't worry, I've got another friend who has who has already offered to make sure we put the thing back together correctly.

  4. #4
    flyin' the friendly skies airbornexp's Avatar
    Join Date
    Aug 2007
    Mahomet, Il. USA
    Yep, that's it. You can't just change the seals. That crank is pressed together. You will have to have a shop separate it and replace the seals or just buy a new crank. I've used hot rods cranks in the past and seemed to work with out issue.

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