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  1. #1

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    Runaway engine again

    I'm tearing my hair out with this ski. I posted this over on the old school forum but I know this side has a lot of experience with troubleshooting issues.
    Ok I've got a '04 xl700 with a 701 62t engine. I bought it not running. Actualy it wouldn't rev up. I started with replacing the coil since it seemed like one side wasn't firing. After that the engine started to run away. compression went dead on one cyl due to burnt piston. from then I tore the engine down new pistons rings crank seals resealed the case all new gaskets, reeds are new, crankcase holds 10Psi. 160 pis compression. Rebuilt both carbs pop off is about 30psi.
    What am I missing
    Can the coil wires being reversed do anything?
    I'm pulling at straws now


  2. #2
    Hydrotoys's Avatar
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    Could be a carb base gasket leak or even a case leak that shows up when it gets hot.

    You DO know that when it happens, just open the throttle all the way, and it should stop. This should only be happening on the trailer.

  3. #3
    Moderator OsideBill's Avatar
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    Runaway is an air leak no doubt about it. are the carbs full of fuel? do you have a leak in a pulse line? nothing else will cause this it is too much air not enough fuel.

  4. #4
    2000 GPRXP 4tec shooter98xpl's Avatar
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    The throttle cable can be too tight making it feel like its running away, make sure there is some slack in the cable. Also, make sure your idle adjuster is not turned in so much as to make it start taking off as well.
    SHOOTER

  5. #5
    Hydrotoys's Avatar
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    making it feel like its running away,
    Even more to focus Shooters same point, you really could be mistaking one for the other. Make sure the carb system is fully closing.

  6. #6

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    Everything is tight. This all started when I changed out the coil. Any chance this is a timing spark problem? There is no Id on the coil which wire goes to which cyl. It happens as soon as the engine starts so tis cold. it will shutoff when I pull the lanyard. If I open the throttle the rpm dosent change or kill it but I can see vapor blasting out the carbs. I thought the reeds were bad but I pulled them last night and they look like new. I had all the exhaust out when I did the rebuild and it is all clear with no restrictions.

  7. #7
    Moderator DrewNJ's Avatar
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    like everyone else is saying, it really sounds like a fuel issue. If your jetting is super lean it will run away on the trailer too.

    Plug wires switched doesn't matter.. can't imagine a coil could make it run away either..

    To much air, not enough fuel...

  8. #8

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    The low speed needles are 5/8 turn out I haven't run the motor more than 10sec on the trailer(scared). Havent had it ion the water yet. should I back out the low speed needles more?

  9. #9

    runaway

    If it has dual carbs check and see if you have one of the butterflies in the carbs out of sinc with the other one ( one closed one partialy or all the way open) Chances of this happening with stock carbs is slim, but I did it when I set up some carbs with the shaft to shaft adapters on a set of tripples I had. Just a Thought (straw).

  10. #10
    rob2337's Avatar
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    I am by far not a 701 expert, but I have rebuilt one of them...

    I had the same problem, it kept on running away, fuel system was 100%. My problem ended up being the timing on the stator was not correct. I pulled the flywheel, rotated the stator a bit and i ran fine after that.

    For some reason, it kept on running away with the stator at the proper timing mark, so I moved it a bit more and it has been running for about 3 years now with no problems.

    Don't ask me why, the stock line up marks should have worked just fine. I am just telling you what worked for me.

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