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  1. #1

    SL 750 engine not running super/carb settings

    Hi I just went out for the first ride and it was almost a succes (:

    The problem is that I've to "work" the throttle to get it to accelerate can't just go wot, then it dies out. It idles fine, I guess it's a fuel problem.
    The previous owner installed an electric fuel pump! I reinstalled the vacum fuelpump (pentagon three outlet) I guess it wouldn't hurt to give it a repair kit properly laid still for a while.
    There is no fuel filter so i think i will give the carbs a repair kit to and install a fuel filter.
    I've adjusted the carbs but have a question. My SL 750 is from 1993 (was i told) the settings i could find are:
    high speed M-7/8 C-1/2 P-5/8
    low speed 1/2
    But there was an extra set of carbs including when i bought it.
    Then i found these settings for a SL 750 from 1995:
    high speed M-3/4 C-1/4 P-1/2
    low speed 3/4
    Is there any way to see which year my carbs are from and are there really a difference from 93 to 95 and do 95 carbs even fit on my 93? Don't know if it helps but my carbs are painted blue? but have no idea if they have been repainted.
    All fuel lines are okay and the restrictor is installed. Don't think the fuel on/off switch has been replaced but could that do any trouble?
    Do you think some repair kits for the carbs and fuel pump would do the trick or do you have any other ideas? (:

  2. #2
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    Yeah... that working the throttle to get WOT sounds like a fueling issue.

    If you haven't rebuilt the carbs... you really should. So many folks toast pistons/engines due to old carbs and fueling issues.
    That pentagon triple outlet fuel pump is a great and needed upgrade. It'll flow way more than a 750 needs... which is just fine. Also remove the autocock (not needed) if you still have it. It's usually attached and plumbed right next to single outlet fuel pump (was on my '94 SLT 750)... sorta looks like a small single outlet pump.

    Carbs. That blue paint (even over the throttle/choke springs which looks like over spray) is stock paint on many of the Fuji engines (780's were black). They are all Super BN38 Mikuni carbs... BUT there are differences between years and models... in the jetting and associated settings. Only way to tell between carbs that were off the engines where you couldn't get engine or ski serial numbers... would be to open them up and check the jet sizes... then figure out which year/model had that size. If you know your engine/carbs are original to your '93 ski.. then use the '93 SL settings for the carbs.

    As for the fuel selector switch. I've heard of them causing issues... but mine never have. During my rebuilds when I'm working the fuel system... I just check to make sure it's not causing any restrictions when on 'ON' or 'RES' and that it prevents flow when 'OFF'.

    I think rebuilding your carbs is your best bet. Lots of good how-to's here on the forum.

    Good luck

  3. #3
    Thanks (:
    Well, when I rebuild the carbs i can compare the two sets of carbs I got and see if they are the same. One of them must be the original.
    There is no autocock on my ski.
    Dosen't sound like I have any reason to rebuild the fuelpump, I have had it open and it all looked fine but to be sure I could check the fuel pressure. The right place would be between the last carb and the fuel restrictor right?
    But I'm quite sure it's the carbs, because now I can't get it to take full rpm at all and it just keeps cut out when I try to "work" the throttle.

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