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Spark Plug - wrong model fitted to trimmer - could it cause problems?

Hi all

I had some problems with my Tanaka trimmer last year and had it fixed (and serviced) by the local repair shop. It's not behaving too well now either so I have cleaned the air filter, and ordered some replacements. I will also replace the spark plug, but was going to try giving it a clean up as well (and check the gap). It was replaced when the machine was serviced.

Upon checking I see they put in a NGK BMR6A. The manual calls for a NGK BMR7A. I *think* the only difference is the Heat Range.

It's all new to me, so I wondered whether this difference in heat range is important or not? Should I be asking the repair shop why they fitted the wrong one? Could it have caused damage to the machine?

Many thanks


  • ColinAColinA Posts: 382
    It is only heat range and means that the plug will run slightly hotter and burn off any deposits forming on the electrodes, 
  • January ManJanuary Man Posts: 212
    edited September 2020
    That's interesting as the plug is quite black actually and needs a good clean.  I run 50:1 - or thereabouts. Only recently discovered how inaccurate the mixing bottle is!

    Thanks for the help.

    EDIT - well, I say quite black, but I don't really know what I'm talking about so here's a pic instead:

  • As @ColinA has said it is only heat range and fitting a very slightly hotter plug will not harm the engine.  Looking at the plug it doesn't seem too bad but would seem to be running rich and may require the carburettor cleaned/adjusted.
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