need help tuning a nitro engine

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    • #12813
      klims
      Participant
      • Posts: 332

      Hey guys,

      yesterday i decided to take my Kyosho TR15 inferno buggy out for a spin. haven’t done so in over 1 year so i figured it was about time. like the fool that i am i started to stuff around with the air/fuel and fuel needles before i even started it up. now i can’t get it to run properly.

      so here comes the question…
      i understand what air/fuel ratio is and what the fuel needle does, but can’t for the life of me understand how i can tune one without the other being set correctly. the seems dependent on each other. to me it seems like i have only one equation and two unknowns. can anyone shed some light on this for me?

      cheers,
      Andrew.

    • #60872
      Avatar photoAaron
      Keymaster
      • Posts: 2146

      Do you mean like the Low Speed and Highspeed needles, plus the throttle stop?

      On my truck it goes something like this.

      Low Speed needle gets would all the way in, then gets let out between 3.5 an 6 turns. The idle need gets turned so that the carb opens about 1mm ..

      Then you have a crack at starting it.

      Let it warm up and adjust the idle need down slightly before soley working on the low speed needle. Usually winding it in a bit to reduce fuel…

      A.

      --
      Site Owner Guy.

    • #60874
      klims
      Participant
      • Posts: 332

      no, see if that was the case i would have had it sorted by now. every thread i have read on the net mentions the high an low speed needles.

      this is what i have…

      [ATTACH]419[/ATTACH]

      and these are the needles i mentioned

      [ATTACH]420[/ATTACH] [ATTACH]421[/ATTACH]

      i’m thinking that maybe i do have a high and low speed adjustment, but my manual labels them differently. can anyone confirm this?

      Andrew.

    • #60875
      Dangerous Dave
      Participant
      • Posts: 229

      dammit I posted a good tuning procedure late last night, but obv something was amiss and it didn’t show up 🙁

    • #60876
      klims
      Participant
      • Posts: 332

      double damnit!

    • #60881
      klims
      Participant
      • Posts: 332

      ITS ALIVE!!!!!!!!!

      after many hours choking on glow fuel, i finally got her going. even managed to rip my rip cord lol.

      needle valve had to be at 1+1/4 turns to run properly.

      can anyone identify what the “needle valve” and “air/fuel” valve are called on their models? or is mine the only one with this setup?

      Andrew.

    • #60883
      Dangerous Dave
      Participant
      • Posts: 229

      well done for both your success and perseverence!

      Main needle, high end, mixture needle etc are the same thing, it’s the main fuel control placed where the fuel line connects to the carb.

      Low end, idle mix, transitional mix screw controls the air/fuel mix at idle and low rpm.

      Some engines do have a 3rd adjustment (mid range) but it is often recommended to leave it alone.

      Your idle stop screw is different again, it does not alter mixtures, it just adjusts your minimum carby opening.

      Tune the main needle by running the car (with a warm engine) at full speed over a distance.

      Then once that is set, tune the low end by idling the car for a few secs, then nail the throttle and observe the response.

      Slow and gluggy means too rich, revving then cutting is too lean.

      hope this post works lol

    • #60884
      klims
      Participant
      • Posts: 332

      thanks Dangerous Dave! i’ll have to give it a try tomorrow.

      still having some issues with running this little beast. took it down to the park today and i seem to be getting mass amounts of nitro leaking after a while. not sure why as yet. i get the feeling like the screws are shaking themselves loose. i might have to look into this so called ‘threadlock’ you speak of. pulled the engine out and tightened up all the bolts i could find. i’ll take it for another run tomorrow and see if that fixes the problem

      thanks for the help

      Andrew.

    • #60885
      Pork_Hunt
      Participant
      • Posts: 349

      I’m not sure if all do, but the auto spares shop I used to work for had thread locker in little “sauce sachet” sized packets for about a dollar if you only intend on using it the once/trying it out.

    • #60886
      Dangerous Dave
      Participant
      • Posts: 229

      any sort of fuel leak will cause erratic running :s

      all metal in metal screws need to be checked often, threadlock does wonders to help.

      Check your tank lid is sealing properly, the O ring seal can be expanded by tightening the small screw in the lid.

      Check the fuel lines for leaks under pressure, and also check the pressure feed from the exhaust.

      Try new fuel and/or a new glow plug. Old glow plugs can be the source of difficult problems.

      All this was in my magnificent lost post lol

    • #60887
      klims
      Participant
      • Posts: 332

      lol thanks for trying dude.

      i’ll look into the auto spares shop pork hunt. thanks for the tip. might just try ebay though. i love stuff that comes straight to my door 🙂

      i learned how important the pressure feed from the exhaust is. caught me out a few times today. i had no idea they were so important.

      got some new fuel the other day and new plugs are in the mail. i had no idea that different fuels gave off different fuels while burning. i hate the smell of petrol usually, but the smell of the yellow fuel i was using was awesome! this new green one smells like sh!t and stings my nostrils lol.

    • #60888
      klims
      Participant
      • Posts: 332

      hey pork hunt is this the stuff you were talking about?

    • #60889
      Pork_Hunt
      Participant
      • Posts: 349

      It would probably be the right stuff to use, but the one I was thinking of was “Loctite Blue”, an automotive threadlock. They have a pretty big range including a gluestick style threadlock. I can’t find anything about the packets I mentioned online, maybe it was a promo thing…

    • #60891
      Dangerous Dave
      Participant
      • Posts: 229

      @klims 226146 wrote:

      this new green one smells like sh!t and stings my nostrils lol.

      then it’s fresh and good to go!

      (and stop sniffing it :huh: ) haha

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