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  1. #1
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    Revo 3.3 tuning issues

    Ok so I got this 3.3 used. It runs pretty good on highspeed. It idles ok once ran a little bit I have tried turning the LSN all kinds of ways. It's running rich on the bottom end. And I can't get it to lean out enough. If you let it idle a bit them try taking off it bogs till it burns up all the excess fuel then it's great on top end and semi good on bottom end. I know it's rich because just putting around till it dies. The muffler fills will fuel.

  2. #2
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    Your low end needle may be too rich. Start back at factory settings, then start tuning again. This always works for me.
    One shot.....One kill, no exceptions

  3. #3
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    I dont think you read it right. I have turned the LSN. All the way in up to 4 out. It changes a little but still too much fuel.

  4. #4
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    Quote Originally Posted by SYN'Z-E-revo View Post
    I dont think you read it right. I have turned the LSN. All the way in up to 4 out. It changes a little but still too much fuel.
    I see, my bad. What glow plug are you running and what kind of condition?
    One shot.....One kill, no exceptions

  5. #5
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    Well I had one in it today and it finally killed it. So it has a brand new one in it. And I got it running good with it. But still have the rich low end.

  6. #6
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    Quote Originally Posted by SYN'Z-E-revo View Post
    Well I had one in it today and it finally killed it. So it has a brand new one in it. And I got it running good with it. But still have the rich low end.
    Hmmmm....have you taken the carb apart? Your low speed needle could be leaking and need new o-rings. Any fuel gunk on the carb or engine?
    One shot.....One kill, no exceptions

  7. #7
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    No. I'm gonna spray everything out to where it's dry. Take carb off. Reset to factory settings. And start over. Then see where it's at.

  8. #8
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    You have to start with the lsn 2 turns out. 4 turns is way too rich.
    "I like rc cars"....."WHAT? YOU'RE KIDDING!"

  9. #9
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    Or your LSN is stripped. If those check out, put carb back to factory settings:
    HSN = 4 full turns countercockwise from fully closed
    LSN = top of needle even/flush with housing (see owners manual for pics.)
    Idle screw = 0.7mm-1.0mm gap from the wall of the carb to the carb slide when closed (usually the width of a standard sized paper clip)

    Only tune with a half tank of fuel, this helps compensate for the leaning as the fuel level drops.
    One shot.....One kill, no exceptions

  10. #10
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by SYN'Z-E-revo View Post
    No. I'm gonna spray everything out to where it's dry. Take carb off. Reset to factory settings. And start over. Then see where it's at.
    I wrote this up a couple years ago, it's been used and viewed over 70,000 times... If the issue is your tune this might help with the tuning issue..

    If there is a stripped HSN, or a crack in the HSN housing, if the o-rings are not seated right, you will have a tuning nightmare... But those HSN threads do strip very easily from cross threading most times...
    Best way to test this is with the engine running spray some WD-40 at the base of the carb, if the idle changes, there's a leak in the body of the carb, or a problem in the HSN housing like I stated....

    Here's that write up,, hopefully it will help.. Best way to tune the LSN is with the pinch test,,, it's in the write up as well.
    http://traxxas.com/forums/showthread....&goto=newpost
    I hope it's just a simple tuning issue, but also go over your head bolts, especially newer engines, they sometimes back off a little with cooling and heating up with running... Tighten them in a star pattern like a 1:1 car tire.

    Robin Williams
    He will be greatly missed...

  11. #11
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    Nothing is stripped. I just tore everything down. Head, carb, everything. Cleaned it all, etc. just now got it reassembled. I'll try running it today. I got everything set back to factory.

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