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My Losi 5T eats spark plugs

Discussion in 'Large Scale RC' started by Greavesy, Aug 23, 2014.

  1. Greavesy

    Greavesy New Member

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    Hi All,

    My new Losi 5T has whats turning into a rather annoying habit...it munches through spark plugs.

    I've now gone through 3 plugs (NGK as per stock) and I haven't even gone through 5 litres of fuel!

    Has anyone else had this problem or be able to suggest a cure (or whether this normal)?

    I'm running two stroke oil at 25:1, using Shell VPower Nitro+ unleaded fuel (99 RON).
    My Losi is in stock trim (with Killer RC Killswitch and Outerwears pre filters on the air and pull starter). I've retuned the carb to stock settings then tweaked it slightly on the high-speed (I did this after plugs 1 & 2 died). First couple of tanks of fuel were breaking in (2 plugs), next couple were tuning and letting rip (plug 3).

    My thoughts were that the carb wasn't tuned correctly from the factory, came with a dodgy spark plug, second plug was also dodgy.
    My last thought is that the Shell fuel I'm using is too potent.

    Please anyone with any suggestions come forward, this is only helping my spark plug supplier stay afloat!!!

    Thanks,
    Greavesy
     
  2. Monkeypiarat

    Monkeypiarat Worlds formost authority on my own opinion
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    #2 Monkeypiarat, Aug 23, 2014
    Last edited: Aug 23, 2014
  3. Antho11

    Antho11 Studio Forums Elite
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    What type of spark plug is it? Is it iridium? I've read that when you use some higher end spark plugs and you run it rich it will burn plugs. If that's the problem use regular spark plugs and then when you have a good tune switch to the better plug.
     
  4. Greavesy

    Greavesy New Member

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    I'm running NGK CMR7H 3066 plugs, these are the standard plugs used in the 5T.
    I've a different two stroke oil for the next can of fuel, maxima super m ester based synthetic blend...maybe this will make a difference
     
  5. Y2daT

    Y2daT Over Powered RC
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    to get the motor tuned perfect you must learn to do plug reads . Pretty simple but time consuming . start with a few fresh spark plugs on hand . and go ahead and warm the motor up on a dirty plug then swap it for a fresh plug and restart the motor and keep it @ idle for 30 seconds or so and cut it off and examine the spark plug . look at the color of the plug if it is black or dark brown it is to rich (to much fuel).. if it is bright white it is to lean ( not enough fuel ) to correct it adjust the L screw accordingly. clean the plug and repeat the process until you get a light tan to creamy colored plug.
    .
    Now on to the H screw we do the same thing only you drive the rc at Wide open throttle and read the plug again ...this time adjust the H screw .... when all is good take some engine temp reads and remember what they are ...in the future for fine tuning for the weather your temp read will help you dial in faster .... if its to hot richen the H screw.... to cool lean it out a tad ... before long you will know what to do by the sound of the engine .
    .
    .
    on the other hand if you have any nitro buddys that tune their nitro stuff regularly they can most likley get it close to perfect by ear ....both motors tune the same. running gas vs nitro means your motor will be affected less by temp changes ...
    and once you learn how its supposed to sound and have a running temp target . you can simply run it and listen ...adjust the H until it sounds good at speed then play with the L screw until you get a nice response between idle and wide open ...then run some more and check the temp occasionally to fine tune the H some more and have fun .
     
    #5 Y2daT, Aug 23, 2014
    Last edited: Aug 23, 2014
  6. Greavesy

    Greavesy New Member

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    Thanks for the info...today's plan will be plug tuning...I've got 5 brand new plugs, I hope that'll be plenty!
    I'll let you know how it goes, thanks again
     
  7. Y2daT

    Y2daT Over Powered RC
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    no problem . and be sure to check for anything loose from the carburetor to the exhaust ... if there are any leaks tuning will be impossible.
     
  8. Greavesy

    Greavesy New Member

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    Well that wasn't too painful...I've tweaked the carb now, looks like it may have been running rich. Now leaned it off, judging by the state of the plug it looks to be OK, well its lighter brown and dry as opposed to the black and wet look that I was getting previously. Time will tell now I guess, and a bit more tweaking - I don't want to lean it off much more as I'm nearly a quarter turn in on both needles away from factory settings.

    Just out of interest, how long should I expect a plug to last roughly?
     
  9. mickyd213

    mickyd213 Studio Forums Elite
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    If all of your used plugs are black, they may have failed due to carbon build up... You can heat up the electrode end of the plug and burn off the carbon and the plugs should be good to use again... Even if only as back ups or plugs for running in engines... You can use a butane torch or even your gas stove...
     

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