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  1. #1
    RC poster
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    Mar 2014
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    6

    problem with throttle servo / carb dont open

    hi all,
    i have revo 3.3 (5309) and last friday i found that my revo is not run properly,
    long story-short i have checked my carburator and i found that it opens just a bit, so i looked at the throttle servo and i found that on the brakes it works just fine but for the gas it moves just a bit or not moves at all (depend on 50/50 or 70/30) we have tried to reset the tqi transmitter to factory, try to pass the throttle servo directly into the reciver (without the opti-drive), we changed the throttle servo, the optidrive, switch the rx flat pack battery, nothing! still wont work, so we try to change the transmitter and we have the 2ch tqi of a slash and we connect it - work just fine, the servo seems to be OK, i orderd from ebay an new 3ch transmitter (the upper part - without the docking) but yesterday i was take apart my transmitter and cleaned it from the inside with some alcohol base cleaner for electronics, when i link my transmitter again it moves the throttle servo a bit at gas and goes full on the brakes, when i connect the servo with the optidrive again it wont move on the gas and brakes are ok.
    another thing i have noticed is that the reverse is switching only when i'm on the brakes, if i put the switch to reverse nothing happend until i press the brakes (the TRX3.3 is off - only electric on).
    doe's someone have an idea?? is it the transmitter in your opinion? or to look for another solution?

    sorry for my english...

  2. #2
    RC poster
    Join Date
    Mar 2014
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    7
    Quote Originally Posted by bdsnir View Post
    hi all,
    i have revo 3.3 (5309) and last friday i found that my revo is not run properly,
    long story-short i have checked my carburator and i found that it opens just a bit, so i looked at the throttle servo and i found that on the brakes it works just fine but for the gas it moves just a bit or not moves at all (depend on 50/50 or 70/30) we have tried to reset the tqi transmitter to factory, try to pass the throttle servo directly into the reciver (without the opti-drive), we changed the throttle servo, the optidrive, switch the rx flat pack battery, nothing! still wont work, so we try to change the transmitter and we have the 2ch tqi of a slash and we connect it - work just fine, the servo seems to be OK, i orderd from ebay an new 3ch transmitter (the upper part - without the docking) but yesterday i was take apart my transmitter and cleaned it from the inside with some alcohol base cleaner for electronics, when i link my transmitter again it moves the throttle servo a bit at gas and goes full on the brakes, when i connect the servo with the optidrive again it wont move on the gas and brakes are ok.
    another thing i have noticed is that the reverse is switching only when i'm on the brakes, if i put the switch to reverse nothing happend until i press the brakes (the TRX3.3 is off - only electric on).
    doe's someone have an idea?? is it the transmitter in your opinion? or to look for another solution?

    sorry for my english...
    I just found my servo will not go wot. It goes about 90 %. I'm curious to see what people say.

  3. #3
    RC Qualifier
    Join Date
    Feb 2012
    Location
    SD California
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    912
    I would take the servo horn off the servo, turn the car on and re center the horn on the servo. If that doesn't work you can try messing with the angle of the carb by loosening the nut on the passenger side of the motor. If that doesn't work try resetting your end points for the servo. If that doesn't work then I would conclude your servo is done.

  4. #4
    RC Racer
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    Mar 2014
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    Peoria az
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    172
    I had a similar problem and it turned out to be the angle of the carb/the angle of the throttle arm.

  5. #5
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    Mar 2014
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    6
    96motorhead, i will try it today.

    Ridebonfire, can you explain what did you mean? what angle?

    lets say my throttle servo on the brakes goes 100% of its way (probably) and on the gas its go 0% when its 50/50 and about 10-15% on 70/30.

  6. #6
    RC Racer
    Join Date
    Mar 2014
    Location
    Peoria az
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    172
    Yeah man here you go.

    First thing you need to do is remove the throttle linkage (the metal link that attaches to the throttle servo and the plastic piece that attaches to the engine/throttle arm). Clean that bad boy out. Mine was all gunked up. Look at my other throttle post - someone else recommended a Integy throttle piece that has a ball bearing (Traxxas is just plastic). I was able to fix my problem without this upgrade though.

    Next, unscrew the carb by the nut in this picture. YOu don't need to take the nut all the way off, just loosen it.
    http://www.flickr.com/photos/120026749@N03/13252592345/

    Next, unscrew the throttle arm allen screw. Again, don't take it out just barely unscrew it so you can move the throttle arm around. Re-attach the throttle linkage if you haven't already done so.
    http://www.flickr.com/photos/120026749@N03/13252938134/

    Angle your carb so the throttle arm is more toward the front of the truck. You can kind of see what I am talking about in this photo. So, HSN should be toward back of truck, throttle arm toward front of truck, and re-tighten the carb nut.
    http://www.flickr.com/photos/120026749@N03/13252938374/

    Next, turn your TX and the truck on. Hold your finger or a screw driver on the side of the throttle arm to apply pressure. Then, slowly apply the throttle to WOT (if you don't hold the throttle arm it will pop off since you loosened the allen screw). Keep turning the throttle arm down (toward the front truck) or up (toward the back of the truck) and listen/look/feel for any binding on the throttle. Once you get the sweet spot, CAREFULLY turn the allen screw and re-tighten. Be careful because if you do it too fast it moves the throttle arm and you lose your position.

  7. #7
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    Mar 2014
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    6
    thanks a lot man! i will try it soon as i find some spare time...

    yesterday i was try to play a little with the opridrive and without knowing what i was doing i had some luck to program it, now with the optidrive and 70/30 on the transmitter the carb is opening up to 6/8 way, seems to be ok right now, with your help i may be able to got it into 100% opening even on 50/50...

    thanks again for the explanations and the photos!

  8. #8
    RC Racer
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    Mar 2014
    Location
    Peoria az
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    BTW I use 70/30 on my TX.

  9. #9
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    Join Date
    Mar 2014
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    6
    Thanks a lot guys, after restarting my optidrive (without realy know what i'm doing) and iv'e change the lock on the throttle arm it works just fine with my TX.

    thanks again,
    Snir.

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