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  1. #1

    Join Date
    Jul 2011
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    Salt Lake City, UT
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    SLT 780 seems to be running very rich.

    Im a noob.

    My brother gave me a pair of SLT 780's and I am working on getting them back to great condition.

    One of them is giving me fits. It is slow to pull out of the hole. revs to about 4000-4200 will stuggle like it wants to plane but wont until I hit a wave that gets the jetpump out of the water then it will rev to 5500 ish and run pretty fast until I let off the throttle. Then its back to 4400 and replay.

    I have been reading several of the post on this AWESOME forum and thanks to all who contribute its been very helpful on several other issues. Some of the post have been talking about carb mixtures High an low settings etc. I have run through a couple of sets of plugs and it seems fine on the high end (when I can get it to the high end) but on the low end it seems very very rich. I have the low screws set to about 1 turn out and Im a little concerned about getting it too lean. (maybe I'm a wuss).

    As a side note it seems to smoke (exhaust) more than the other one and the exhaust area is covered in oil.

    I know it is hard to help with out seeing it. I am working on getting the Compression. will probably do this on Mon.

    I am wondering if the oil injector is pumping in too much oil and this is more likely than it running too rich.
    (I am running theses at an altitude 4500 msl and im sure the jets are stock)


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
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    Which model years?

    Oil pump linkage connected and working?

    Have the carburetors been rebuilt?

  3. #3

    Join Date
    Jul 2011
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    Salt Lake City, UT
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    8
    Sorry Both are 96 SLT 780's.

    the oil pump linking is connected and appears to be working.

    I did tear down and clean the carbs yesterday. haven't "rebuilt" them yet. planning on ordering kits this weekend. which leads me to another question. where does someone get the pop off test tool?

  4. #4
    johnsonmtz's Avatar
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    Oct 2006
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    #1, you need to completely rebuild the carbs with new kits. Order them from John Zigler because he includes only the parts needed for a Polaris Mikuni carb rebuild including new needles and seats.

    I ordered my pop-off tester from parker Yamaha: http://www.parkeryamaha.com/mikunipo...er0-30psi.aspx

    Your 780 should have good crisp acceleration all the way up to 6300 RPM.

    KJ

  5. #5

    Join Date
    Jul 2011
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    Salt Lake City, UT
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    very good. thanks for the links and info. I will order the kits Monday and update after. thanks again.

  6. #6
    Banned User
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    You said you are running at high altitude? Where are you located?

  7. #7

    Join Date
    Oct 2009
    Location
    NE Wisconsin
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    27
    I had the same issue with my SLT780. It ended up the exhaust was getting very hot and the hose blew a hole. This allowed the exhaust into the engine compartment starving the engine of oxygen. For what ever reason when I would jump a wave the RPMs would shoot-up and would go fine for a while. Check these hoses and feel the muffler after running to see if it is running hot. Mine ran 210F. Good luck.

  8. #8

    Join Date
    Jul 2011
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    Salt Lake City, UT
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    I'm in Utah.

    Thanks for the muffler suggestion hadn't thought if that, I'll check it out.

  9. #9
    Banned User
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    If you are at high altitude, the carbs need to be adjusted to compensate for that. What elevation are you at? Somewhere around here are the high altitude settings for that ski.

  10. #10

    Join Date
    Jul 2011
    Location
    Salt Lake City, UT
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    Hey Bryan,

    I will mostly be riding this around the 4500 Ft Altitude here in Salt lake city and Lake Powell. I have thought about the high alt settings I will have to dig a little deeper into the manuals here and see if I can find a good starting point for them.. thanks again

    That being said I'm not sure that is the problem I am having with the power loss though since both my skis are jetted the same and the other runs great. pulls hard and runs strong. It is a little rich as well. I plan on re-jetting them both at the same time.

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