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Engine sounds like its flooding....

Discussion in 'Race - Engines, Tuning & Exhaust' started by lout, Jan 4, 2013.

  1. lout

    lout Studio Forums Elite
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    Hi All,

    It's not really on onroad car, (ACME Monster T) but it's a nitro issue. It's been a long time since I've run nitros and I'm trying to help out a family friend.

    The problem is that when you apply full throttle (or even 3/4) the engine sounds like it floods and dies. It sounds boggy and dies.

    To my mind that sounds like it's getting too much fuel as I believe ( and I could be wrong) that when it lean's out and not get enough fuel it starts reving harder and more high pitched.

    It was set at 2.5 turns and I've wound it in 1/4 turn at a time to 1.5 with no change

    Any ideas ?

    Thanks guys
     
  2. Greenie

    Greenie VillAge iDioT
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    all filters clean, fuel and air??
    when its idling, spray a little WD40 around the Carbi, to make sure there is no air leak there, all the fuel lines good??
    the low speed needle is good? good acceleration???
     
  3. Akkip

    Akkip Studio Forums Elite
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    Check the low and high-speed needles
    A friend of mine bought a slightly old buggy a while back, and it was VERY picky on the high/low.
    Other that, make sure that youre adjusting the right screws. Cause if youre turning the air/fuel screw, you might end up making more work for yourself.
    Good luck :)
     
  4. lout

    lout Studio Forums Elite
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    Thanks for the luck I needed it. Spent all day on this thing. Found out that my glue igniter battery was dead replaced that with some okay cells from an old pack.

    Eventually hot the low speed needle set. What a monumental pain that was. Having it die or rev too fast or both. Got that sorted, but now try and lean out the high speed needle as its still bogging down going from half to full throttle.

    1/8th of a turn and it seems to have affected the low speed needle as it won't idle any more.

    So at the moment it's in a state of mostly working but it's still not right especially with the high speed needle
     
  5. lout

    lout Studio Forums Elite
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    Filters are clean, fuel is new 20%. Car us only 2 weeks old. Engine was broken in as per the instructions is was told and has now had about 10 or 11 tanks through it

    Car will accelerate to half throttle now which us better than before but it still won't go WOT. But it sounds like its reving at wot tho. There is also the plune of smoke from the exhaust as well

    Didn't try the wd40 round the carbi body tho
     
  6. lout

    lout Studio Forums Elite
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    Isn't the screw that's on top (the big one) the high speed needle ?
     
  7. Akkip

    Akkip Studio Forums Elite
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    Thats usally the mixture
     
  8. jaloos

    jaloos Mod, Staff Member and Ghetto Fabricator
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    Isn't there a difference in the needles with a slide carb and a rotory carb?
    These are rotary carbs right?
     
    #8 jaloos, Jan 7, 2013
    Last edited: Jan 7, 2013
  9. hvydingo

    hvydingo Studio Forums Elite
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    Put the high/low speed needles back to factory settings,make sure you got a good glow plug,and clean air filter.Watch not to over oil the filter though.Pull the air filter off and set the idle screw to were their is about a 1/16th opening on the barrel.You can also check to make sure the fuel lid is making a good seal and the exhaust coupler isn't damaged making it suck air.The initial problem sounds to me like the high speed is to lean,and it's starving for fuel.I always get my high speed set first then the low speed.IMO I would get the manual out and find the factory settings and go from their.
     
  10. jaloos

    jaloos Mod, Staff Member and Ghetto Fabricator
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    Well put X2
     
  11. jessicarobin

    jessicarobin New Member

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    If you run your car out of gas, the fuel system usually has ingested air, which starves the injectors of fuel if you try to start it immediately. You will want to wait a few minutes with the key in the "on" position so the fuel pump can run and perhaps bleed out the air. Flooding is usually accompanied with a strong smell of raw fuel.
     
  12. 6sharky9

    6sharky9 Studio Forums Elite
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    I agree with going back to factory setting and re start....Always allow the motor to be at operating temps before actually trying to tune it..What might smooth out a nitro motor when its cold will always change when hotter..may people burn up motors this way..When its cold the only way to get it to run smooth is generally to run it lean..As it gets hotter and hotter you start to notice awesome power but you are at serious risk as it becomes more and more lean. A well tuned motor always runs like crap until it gets to operating temperature...

    An engine bogging doesn't necessarily mean its running rich..it can bog as well from being too lean

    You want to tune the high speed needle first once warmed up..never tune the low speed needle first...if you need to run the idle up to keep it running its ok to do that...when you start on the low speed needle you will know to turn the idle down as you get closer to the proper tune.

    Get it so you get a good amount of smoke and power then you can start working the low speed needle to get a good transition from low speed to high speed power without any hesitation or bogging.

    When you think you have the low speed correct you can test that by pinching the fuel line as close to the carb as you can...If it idles up a little then dies out within a few seconds (about 3 to 4 ) you have it adjusted right.

    If it takes for ever to die out you are too rich.
    If it revs super high and dies out almost immediately its too lean.

    Only make 1/16 to 1/8 degree increments of adjustment...These nitro motor are more sensitive than you might think when tuning...Just the littlest amount in adjustment can make all the world of difference in performance and tuning.

    Always rev the motor a few times and let it sit and idle after an adjustment and allow it time to adjust to the change.

    Always make sure you have a fresh plug as well installed..A bad tune will destroy a plug in a hurry...Most don't think about that and can never get a motor to run right as the plus was destroyed. Just because it is good enough to start the motor doesn't mean it good...Its not cheap to run a nitro vehicle but if you want it to be the best it can be..Always keep a fresh plug on hand.

    If you've done all you can and still have problem you may need the motor serviced as it may have a vacume leak or possible a worn piston and sleeve.
    Some other common areas to check are the back plates, the carb,the head gasket,exhaust gasket or seal and in some cases you can leak through a bearing.
    Also a bad gas tank or fuel line can cause you a headache

    Clean the motor up and run it again..anyplace you might find oil on the outside of the motor will be an indication of vacume leak.

    Good luck to you and hope you get it worked out.
     
    #12 6sharky9, Jan 10, 2014
    Last edited: Jan 10, 2014
    lout likes this.

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