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  1. #1

    96 Polaris SLT Top-End Rebuild problems

    Hello,
    If anyone out there can help me with this problem I would greatly appreciate it.
    I recently rebuilt the top end of a Polaris 96 SLT 700 with a complete piston kit. All gasket and rings were replaced. I cleaned the carbs and replaced the gaskets. I drained all previous gas and filled it with 93 ethanol fee. Plugs were also replaced.
    We then took it to the water and she started up great and ran OK for a few mintues but then would would quit suddenly. I could start it back up without problems but it repeated to quit a few more times. It would quit at full throttle, 1/2 throttle or idle unexpectadly.
    I took it back to shore and replaced the plugs again, cleaned water seperater, check all fuel lines and filters which all checked out ok.
    I took it back out and again it would quit suddenly so I again thought it may be a fuel/carb problem so I replaced the carbs and fuel pump with one off of my other SLT. Again the same problem occurred.
    At this point I am lost and am looking for any advice.
    Thanks,
    Jim


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome

    Did you open and inspect the electrical box when you did the engine work?

    If there is water inside it will cause trouble.

  3. #3
    No I did not check the electrical box. What specifically should I look for?

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by connelja View Post
    No I did not check the electrical box. What specifically should I look for?
    Water, corrosion, loose connections, squished or frayed wires.

    Everything inside an electrical box should look like new, even many years later.

  5. #5
    ripcuda's Avatar
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    Quote Originally Posted by K447 View Post
    Everything inside an electrical box should look like new, even many years later.
    True. I bought a pretty beat-up looking 95 SL 750 for parts. When I opened the ebox, it was the cleanest looking ebox I had ever seen. No kidding, I'd have thought this was a brand new, off the showroom floor ski by just looking at the inside of the ebox. Of course, I've seen many others that were corroded and yucky inside too.

    Cheers!

  6. #6
    Thanks for your responses. I opened the ebox and everything looked good. I again check all my fuel lines and vents which all appeared to be ok. We then attempted to fire it up again on the water and it sounded like it tightened up and sure enough when I limped to shore it had 0 compression on the back cylinder but about 120-125 on the front.
    I should know better to try and run this again but everything thing seems to check out. I have two last thoughts what it may be and hope someone can help.

    1. Could it be an oil pump failure and the back cylinder got too hot. (is there a sensor that causes the engine to quit if it gets too hot?) I took the lines off of the oil pump and started it. Small amounts of oil were lightly ejected. Is this enough oil? Should I just run pre-mix and forget the oil pump if I decide to rebuild this?

    2. I have another SLT 700 and I could rob the ebox off of this one to see if it is an electrical issue?
    I know I am rambling but we can't figure this out.
    Thanks

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by connelja View Post
    Thanks for your responses. I opened the ebox and everything looked good. I again check all my fuel lines and vents which all appeared to be ok. We then attempted to fire it up again on the water and it sounded like it tightened up and sure enough when I limped to shore it had 0 compression on the back cylinder but about 120-125 on the front.
    I should know better to try and run this again but everything thing seems to check out. I have two last thoughts what it may be and hope someone can help.

    1. Could it be an oil pump failure and the back cylinder got too hot. (is there a sensor that causes the engine to quit if it gets too hot?) I took the lines off of the oil pump and started it. Small amounts of oil were lightly ejected. Is this enough oil? Should I just run pre-mix and forget the oil pump if I decide to rebuild this?

    2. I have another SLT 700 and I could rob the ebox off of this one to see if it is an electrical issue?
    I know I am rambling but we can't figure this out.
    Thanks
    You need to first open up the damaged cylinder and figure out why it failed this time. Lubrication failure will look different from a fueling failure, debris damage, etc..

  8. #8
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    I would be looking into the oil system. Its something I go through on every new to me ski. I make sure all lines are flowing clearly, the filter is clean, and the check valves at the carbs are operating properly. I properly maintained oil injection system rarely fails. The pumps are near bullet proof. The pumps don't fail, its usually an issue with the lines.

  9. #9
    Sooo...how much for the 780? stimpsonjcat's Avatar
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    When you did the rebuild, did you check to make sure the oil pump was sending oil to each feedline?

    I run a gallon or so of slightly over-oiled premix in my rebuilds at first and then once running I pull the oil lines individually to make sure they are moving oil. You can disconnect the throttle to oil pump rate adjusting arm and just move it to max at idle to check. It won't be squirting out, but should be producing oil.

    Even a few minutes with no or little oil will kill these things, even more so for a new engine.

  10. #10
    ripcuda's Avatar
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    My '94 750 injected the oil below the carbs in the intake manifold. My '95 750 engine I just transplated into the SLT injects the oil above the carbs in the flame arrestor throats. It's nice to be able to see the oil injectors dribbling out oil when the engine is running (w/ flame arrestor opened up).

    I know the Fuji 780's injected directly into the carbs... so where do the domestics inject oil?

    Cheers!

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