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  1. #1

    98 XL1200 - Smoking and Over-rev

    So I finally got the top end put back on my ski where it had been rebuilt before and the mechanic didn't use threadlocker and torque the bolts down that hold the cylinders down on the block. Anyways, when it's sitting on the trailer, it smokes something awful (a lot more than my other 2-stroke ski), and after a few seconds it starts revving out of control. I am able to kill it with the tether switch. When it's in the water, it doesn't rev up, but it does still smoke a lot. It also acts like it doesn't want to run well until it gets up to about 4k rpm.

    I'm thinking I might back in down in the water on the trailer and let it run, then spray the engine with carb cleaner to see if I can find a vacuum leak somewhere. I'm not sure what to do about all the smoking. Any ideas?


  2. #2
    First, you need to locktite and torque the cylinder and head bolts. Then check the throttle cable cable adjustment if it still revs high. Smoking is usually too much oil. Ditch the oil injection and go to pre-mix.

  3. #3
    powerstroke specialist mikegp's Avatar
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    Quote Originally Posted by gntim View Post
    First, you need to locktite and torque the cylinder and head bolts. Then check the throttle cable cable adjustment if it still revs high. Smoking is usually too much oil. Ditch the oil injection and go to pre-mix.
    you need to do what? loctite the head bolts? OMG. good luck.

  4. #4
    Mighty Mouse's Avatar
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    Check the cable on the oiler. It may have gotten hung up on something and it stuck in the wide open position.

  5. #5
    Sorry, I should have specified that it's already been converted to pre-mix. Now that I think about it, I let my buddy mix the oil for that ski while I was doing the other one the last time I filled up (won't make that mistake again). The throttle cable does have a little play in it (about the same as my other ski). Any other ideas on why it would be revving up out of the water? From what I've read about a lean rev (leak, etc.), it would probably run away and I wouldn't be able to shut it off with the tether switch. Is that a safe assumption?

  6. #6
    Yamaha artisan Cutlass's Avatar
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    The high rev/run away rev could be a crankcase leak. Pressure test the engine and spray suspect areas with soapy water.

  7. #7
    Quote Originally Posted by Cutlass View Post
    The high rev/run away rev could be a crankcase leak. Pressure test the engine and spray suspect areas with soapy water.
    That's what I'm afraid of. There's not a lot of room inside the hull to work on this 1200. Is it possible to do a pressure test inside the hull and still be able to see all the places it may be leaking? I was also thinking of backing the ski into the water, starting it, and spraying it with carb cleaner to try to find any possible leaks. It's worked well with other types of engines before, it shouldn't hurt this 2-stroke should it?

  8. #8
    My 1200 was doing the same thing , if You have remover and checked the carbs , make sure U use all new intake gaskets , I was trying to save few $ and used some sealant on the old gaskets and end up ..... up my cylinders ,and check your PV just to make sure the pins are in

  9. #9
    Steveard's Avatar
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    Mine did this and I found a gasket was on wrong. You can pressure test it in the PWC. You just need to pull the carbs off and cap them including the three nipple conections above the reed cages. Then pull the exhaust right after the three lines merge and cap that. Use one of these spots to add a connection to read the pressure and to pump it up. I used 3/4" thick plastic plates cut out for all the caps with rubber gasket pieces cut out that I got at a hardware store. I then drilled and tapped a hole in the cap for the exhaust side and added a pressure guage (One for checking the pressure for basketballs), a quarter turn shutoff and an adapter for a bicycle pump. You can also buy this as a kit. When I first had the leak I used a spray bottle with soapy water to find it.

  10. #10
    Yamaha artisan Cutlass's Avatar
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    Quote Originally Posted by jackawa View Post
    My 1200 was doing the same thing , if You have remover and checked the carbs , make sure U use all new intake gaskets , I was trying to save few $ and used some sealant on the old gaskets and end up ..... up my cylinders ,and check your PV just to make sure the pins are in
    Quote Originally Posted by Steveard View Post
    Mine did this and I found a gasket was on wrong. You can pressure test it in the PWC. You just need to pull the carbs off and cap them including the three nipple conections above the reed cages. Then pull the exhaust right after the three lines merge and cap that. Use one of these spots to add a connection to read the pressure and to pump it up. I used 3/4" thick plastic plates cut out for all the caps with rubber gasket pieces cut out that I got at a hardware store. I then drilled and tapped a hole in the cap for the exhaust side and added a pressure guage (One for checking the pressure for basketballs), a quarter turn shutoff and an adapter for a bicycle pump. You can also buy this as a kit. When I first had the leak I used a spray bottle with soapy water to find it.
    A '98 XL1200 should be the 65U non-powervalve engine.

    OP, you can pressure test the engine in the ski, but you most likely won't be able to check most of the suspect areas. So basically you can confirm there is a leak and maybe check a few spots, but then you'll have to pull the engine anyways to check the rest of the spots and repair the leak (if its a crankshaft seal or a crankcase half leak). Here's a good thread on pressure testing the 65U 1200 - http://www.greenhulk.net/forums/show...essure-testing

    I cut up an old inner tube and used it to seal off the intake and exhaust for the pressure test. Here's some pics:





    I laid those rubber pieces down and then bolted the carbs and exhaust pipe on to seal up the engine

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