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  1. #1
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    Mar 2018
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    Problem with cutoff

    So I have a problem with my 3.3 Jato. Whenever I brake the engine stalls out on me. All the carb settings are factory or near factory. It idles fine and accelerates fine. The gap doesn't close when the brake is applied. The controller is set to 50/50 and when switched to 70/30 it cuts off. Can anyone help?

  2. #2
    RC Qualifier westoakmech's Avatar
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    Dec 2011
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    I would go over your tune really well, it is probably tune related
    Will it stay running if you let off easy?
    Rusty 2.5R,T-max 2.5 & 3.3,Summit VXL Nitro 4-tec

  3. #3
    Marshal Double G's Avatar
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    Will it start only with the tires off the ground and even so the tires spin when starting? Clutch shoes/springs broke.
    The Super Derecho

  4. #4
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    its does idle on the 50/50 setting (controller), not on the 70/30.

  5. #5
    RC Qualifier westoakmech's Avatar
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    If it idles on 50/50 and not 70/30, then you have a idle gap, or linkage setting problem.
    You can take the horn off the servo, set it to 70/30, and then reset your horn.
    I remove the air cleaner, then reset the horn. I set mine up so the horn has to move a little bit before the slide moves. That way I know for sure my slide is going back to idle.
    Rusty 2.5R,T-max 2.5 & 3.3,Summit VXL Nitro 4-tec

  6. #6
    RC Champion olds97_lss's Avatar
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    Dec 2003
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    Dragging clutch, idle screw not set right, bad clutch bearing. It may idle ok with the remote at "idle", but when you apply brake, the lever pushes on the carb, so if your idle stop screw isn't being rested on when the remote is at "idle", then it's going to close further when you apply brake.

    The bearing or dragging clutch will cause excess drag to make the stalling issue worse.
    Expert rigging at it's best!

  7. #7
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    Apr 2018
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    Hi, i'm new here and i need some help urgently
    I have a jato 3.3 and i rebuilt the carburetor and the engine wont Idle on 1+mm gab, i manage to get him on idle on aprox 4mm gab and run ok,but when i apply the brake he is cutting off.
    i set LSN and HSN as factory setting and start from there ,but cutting off when apply brake.
    i toke the return spring off and adjust the linkage and also set the servo horn referent positions.
    this is driving me crazy,Idling on a 4mm gab and still cut off when you brake.
    i appreciate any help.
    thanks

  8. #8
    RC Champion olds97_lss's Avatar
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    You sure your clutch isn't grabbing? Maybe your clutch spring broke and it's dragging causing the engine to need a higher idle to keep going.
    Expert rigging at it's best!

  9. #9
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    Apr 2018
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    i will take the engine off and check everything again.
    they had a nasty crash that they broke the engine block,i just assemble a new block with a new carburetor body.
    the clutch was fine and looks new. but i will check this again.
    before i was thinking maybe the flywheel might be a bit loose but i tight that and with a drop of locktite.
    This have a Q1 2.4 Radio and i can get the servo to (0). i did adjustments on the Idle-Lsn-linkage and servo horn and still do de same.
    when you apply brake the Carb linkage push the engine, but the carb gab don't closed fully tu cut off the engine but he cut off.

  10. #10
    RC Champion MaXXL's Avatar
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    If your carb is at factory settings and the idle gap is not closing when you press the brakes, the carb and linkage is probably not the issue.

    Must be something else. Check the clutch and exhaust and make sure all the screws holding the engine together are tight including the glow plug.
    10 RCs and counting 😅

  11. #11
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    Apr 2018
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    Hi, thanks for your tip,
    i toke the engine out and check Flywheel-clutchbell bearings and clutch and they are ok.
    Cooling head is tight and back plate too'.
    rear bearing and front bearing of the crankshaft in place and no leaks of falls air.
    One thing i think about is the nozzle where the fuel is running in to the engine is getting blocked with the LSN when he slide back to Idle position because the two splits (groove) on the nozzle to keep fuel running and keep the engine running are not open. and there no way to get there because is built in the Carb body.
    on the picture below you can see the Idle point

    sorry for some reason i can load my picture

  12. #12
    Marshal Double G's Avatar
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    When you rebuilt the engine did you put the cutout in the piston facing the carb?
    The Super Derecho

  13. #13
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    Hi, thanks for help.
    well i was thinking that,but i put the piston cut facing to the exhuast.

  14. #14
    Marshal Double G's Avatar
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    It needs to face the carb. As well as the oiler hole in the rod.
    The Super Derecho

  15. #15
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    Apr 2018
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    yes, problem resolve. as same as other engines
    Thanks pall

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