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  1. #1

    94 750SLT Quick Carb Question

    I have the above ski that I put a new engine (and triple pump) in last year. It works pretty well, but I was not quite happy with the wash on the center piston. I played with the high speed setting but never really got the wash where I was 100% happy. I pulled the carbs off and took them apart to make sure there isn't anything wrong with the center carb. It looks OK. I also checked the pop off pressures and they were all high, 24psi-28psi-24psi. From reading the Mikui manual, it sounds like the popoff only affects the low speed mixture.
    • If I adjust the pop off to the 12 to 18PSI in the manual, will this affect my wash at all?
    • I have read you should not cut the springs to lower the popoff. I bought the Winderosa rebuild kits and they have the different springs, but that is about all I need out of the kit. I'm having a hard time convincing myself to spend $120 for $6 worth of springs. The rest of the kit is gaskets, o rings and the diaphram.
    • Would it be smarter to replace the needles and seats? The popoff is high, but they still seal well. Maybe new needles and seats will pop off lower?


  2. #2
    cameron da river rat's Avatar
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    you probably have 1.5's in there and switching to 2.0 will put you on the high side of spec depending on altitude, here in texas i'm around 300' above sea level, i just did a set of polaris carbs for a 650 this week and got about 21 psi with 1.5's and switched to 2.0's and brought them down to 16psi.

    although i don't like cutting springs, when you don't have what you need, you have to make due with what you have.

    changing pop off will not effect total fuel flow so it really won't change your piston wash..................to an extent..................if you can get perfectly metered fuel at any rpm then yes, it may clean up your piston wash a little.

    what settings do you have your center piston at? how do you have your fuel system set up? the center is set at the leanest of the settings because the pto takes the bulk of the load so its set up richer and the mag takes all the heat from the magneto so it is also set up richer, i think center is only like 1/2 turn out on the high.........if memory serves me right.

  3. #3
    Quote Originally Posted by cameron da river rat View Post
    you probably have 1.5's in there and switching to 2.0 will put you on the high side of spec depending on altitude, here in texas i'm around 300' above sea level, i just did a set of polaris carbs for a 650 this week and got about 21 psi with 1.5's and switched to 2.0's and brought them down to 16psi.

    although i don't like cutting springs, when you don't have what you need, you have to make due with what you have.

    changing pop off will not effect total fuel flow so it really won't change your piston wash..................to an extent..................if you can get perfectly metered fuel at any rpm then yes, it may clean up your piston wash a little.

    what settings do you have your center piston at? how do you have your fuel system set up? the center is set at the leanest of the settings because the pto takes the bulk of the load so its set up richer and the mag takes all the heat from the magneto so it is also set up richer, i think center is only like 1/2 turn out on the high.........if memory serves me right.

    So stock, the needles and seats should be 1.5's? I looked at the needle and there was no markings on it. I didn't pull the seat out though. I am at about 1600ft above sea level. I currently have the center high screw out about 1.5 turns. The PTO and mag are slightly less than one turn. The wash on the PTO and mag are good, even a bit excessive. The center has very little wash, only a couple of small spots by the transfer ports.

  4. #4
    blegan's Avatar
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    factory settings

    The correct pop off pressure is 10-18 psi, & low speed 1/2 turn & high speed 1-1/4M, 3/8C, 7/8P those are the factory settings. If you just need various springs to adjust your pop off, you can get just springs with out buying the whole kit. I also agree that if you have a 1.5 needle and seat you need to put in a 2.0 or 2.5

  5. #5
    Quote Originally Posted by blegan View Post
    The correct pop off pressure is 10-18 psi, & low speed 1/2 turn & high speed 1-1/4M, 3/8C, 7/8P those are the factory settings. If you just need various springs to adjust your pop off, you can get just springs with out buying the whole kit. I also agree that if you have a 1.5 needle and seat you need to put in a 2.0 or 2.5

    I ordered 2.0 needles, seats and 65 springs today from Dennis Kirk's. I couldn't get the individual parts locally. We will see how that works.

    BTW, how / what did you use to strip your decals? Mine look pretty ratty. I tried to remove some, but I decided what was left looked worse! LOL!

  6. #6
    cameron da river rat's Avatar
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    your center cylinder is way rich...............if you have it out 1 1/2 turns its only suppose to be 3/8 of a turn.

    i wouldn't mess with pop off if it runs really good, if it has a bogg or hesitation then yes, i'd switch pop off pressure.

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