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  1. #1
    Myself's Avatar
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    Pair of SL 780 with problems

    Both are '96 model.
    Ski #1---Already pre-mix. Fuel lines have been replaced. Took off and thoroughly cleaned carbs (they were already clean). Compression 120 mag 120 cen 112 pto. Starts fine, idles fine, Runs great mid to top end. Has an off idle to lo-mid transition bog that I can't seem to adjust out. If you slowly increase throttle past lo-mid then it's fine. If you try to just stab the throttle it bogs for a bit then takes off. I don't see any return line restrictor, are these suppose to have them?

    Ski #2---Converting to pre-mix in the next couple days. Fuel lines have been replaced at some point. Thoroughly cleaned out the (already clean) carbs. Compression 110 mag, 105 cen, 110 pto. Starts up fine, idles like it has a miss. Good spark at all three plugs. Very boggy feeling with low power. Only wants to run about 25mph at 4200 rpm. If you hop it out of the water a bit and unload the pump the RPM's will pick up and the power seems to come on. You can get 43mph out of it @ 6200 rpm's. But if you make a hard turn or slow down it goes back to its bogging. After messing with it for a bit I noticed a milky oil film all over the carbs ( had flame arrestor off for tuning). Does this point to a possible reed problem? The carbs appeared to have spit this out.

    Thanks in advance.


  2. #2
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    #1, the restrictor is built into the carb rack. No external restrictor.

    Can you see fuel dripping from the carbs when idling? (maybe a bad needl/seat O ring)

    Did you reset the low screws back to factory settings?

    #2, Is your MFD red light flashing?

    Was the impeller replaced?

    Is the impeller damaged?

    Possible cavitation.

    It's normal for the carbs to spit a little fuel out the top. Not alot.

  3. #3
    Myself's Avatar
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    No fuel dripping when idleing. I checked popoff before I re-installed the carbs.

    Reset all lows to 5/8, front and center highs to 3/4 and pto high to 1. Ran a little better if I leaned highs out 1/4 turn but only to the extent of a leaner, hotter burn.

    Yes, light is flashing and saying Fuel. But there is 1/2 tank.

    No cavitation problems on either ski, and pump bearings are smooth with no play.

    What kind of timing mark should I see through the inspection hole while front piston is at TDC? I'm wondering if it sheared a key.

    Pulled carbs and intake off and inspected reeds today. They look like brand new. Pulled the oil pump and fabbed up a blockoff plate also.

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    "Low fuel" with gas in the tank normally means a bad float. You can get a replacement float from John Zigler or Sharp's Marine for around $30. That will eliminate the red light and "limp mode", but for the time being, disconnect the grey wire inside the elec box to disable the limp mode.

    Just remember, you have no reserve, so you will need to pay attention to your fuel level.

    Was the impeller replaced on #2? Can you read the numbers on the impeller looking through the intake grate?

    I couldn't tell you what the timing mark would be. It's near impossible to get a timing light inside the hull with it running and see it.

    If it's in question, I'd be removing the stator cover and removing the flywheel. That way you can see the woodruff key, and verify the stator timing mark is in line with the case halves seam.

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