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  1. #1
    skigolfnut's Avatar
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    Pro 785 - thin Black wire is getting warm when cranking engine

    I am working on my limited pro for the upcoming race and I noticed when I crank it a bunch I reached in to move the wires around and the small black wire running through the harness is really warm??

    any ideas?

    so I worry, or it is just a by product of a lot of cranking?


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Remove, clean and carefully check the heavy Black battery cable, at both ends. Somewhere there is a poor connection.

    The thin wires (of any color) should never get warm. The reason for it getting warm is that the heavy battery cable is not providing a low resistance connection between battery negative post and engine case.

  3. #3
    skigolfnut's Avatar
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    thanks, I am on it

    ---------- Post added at 07:52 PM ---------- Previous post was at 06:39 PM ----------

    yep, took the black ground wire off the bottom of the engine and on the battery and it had a small crack around the fitting where it connected to the engine, I had a new spare so I put it on,

    thanks,

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by skigolfnut View Post
    ... it had a small crack around the fitting where it connected to the engine,..


    Does that battery cable actually connect to the engine crank case directly or to the bed plate under the engine?

    The blue Fuji engines have the battery negative cable connecting to a small grounding bolt on the bed plate. The problem is that if the bolts connecting the bed plate into the bottom of the engine case became corroded or loose there would be a poor electrical connection between bed plate and engine, which would cause electrical problems (poor engine ground back to the battery).

    Since it is impossible to see those engine bolts underneath the bed plate, they are easy to ignore.

    One work around is to move the engine end of the battery cable to one of the intake manifold bolts at the PTO cylinder. That ensures the negative cable really does have a solid, zero ohm electrical connection to the engine itself, not just to the bed plate.

  5. #5

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    it bolts to the bed plate

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Quote Originally Posted by K447 View Post


    Does that battery cable actually connect to the engine crank case directly or to the bed plate under the engine?

    The blue Fuji engines have the battery negative cable connecting to a small grounding bolt on the bed plate. The problem is that if the bolts connecting the bed plate into the bottom of the engine case became corroded or loose there would be a poor electrical connection between bed plate and engine, which would cause electrical problems (poor engine ground back to the battery).

    Since it is impossible to see those engine bolts underneath the bed plate, they are easy to ignore.

    One work around is to move the engine end of the battery cable to one of the intake manifold bolts at the PTO cylinder. That ensures the negative cable really does have a solid, zero ohm electrical connection to the engine itself, not just to the bed plate.
    May not be a bad idea to install a ground strap from the battery cable/bed plate connection to the engine like K447 mentioned on all the Fuji engines just to eliminate that problem.

    Something like this?

    http://cgi.ebay.com/COPPER-WOVEN-WIR...item5642df2c99

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by xlint89 View Post
    May not be a bad idea to install a ground strap from the battery cable/bed plate connection to the engine like K447 mentioned on all the Fuji engines just to eliminate that problem...
    Actually, simply moving the negative battery cable end from the bed plate to the intake manifold bolt may be the simplest solution. No extra parts to buy or install. Direct electrical connection to the engine block.

    The copper ground strap approach will work too, of course.

    That Fuji/Polaris originally connected the battery cable to the bed plate to begin with just seems like a poor design.

  8. #8
    skigolfnut's Avatar
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    thanks, It seemed a little better with the new ground wire, but I think I will try and move my ground up to the block just to be sure,

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by skigolfnut View Post
    ... I will try and move my ground up to the block just to be sure,
    Post up clear before and after photos of the change.

    Others will be interested in doing the same modification.

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