Spark Plug Gap Size for Honda Lawn Mower

beefmaster on 30/09/2025 - 14:21
Last edited 30/09/2025 - 15:19 by 1 other user

I have a Honda lawn mower HRN216VKUA. According to the manual, the recommended spark plug is an NGK BPR5ES with a gap of 0.7–0.8 mm. However, the NGK BPR5ES I purchased from Repco came with a 0.9 mm gap.

This has left me confused, as the gap size doesn’t match the manual’s recommendation, and the Repco staff were unable to give me a confident explanation about the model or gap size.

So, I’d like to know:

Are there different versions of the NGK BPR5ES?

Where can I get one pre-set to a 0.8 mm gap?

Is manually adjusting the only option?

EDIT: Thanks, I will buy one and adjust to spec. Was hopping to avoid manually changing it.

Automotive Honda Lawn Mower NGK Spark Plug

Comments

  • apsilon on 30/09/2025 - 14:39
    +6

    You always manually gap a plug. No guarantee they come out of the box actually set to what they claim to be.

    • Dr Phil on 01/10/2025 - 17:16
      -1

      Yes, you gap a spark plug with a feeler gauge. And very cheap to buy.
      Though the difference between 0.8mm and 0.9mm is basically "margin of error"

      Wont make any difference to the lawn mower.

      Just screw in the new spark plug OP and start her up!

      VROOM!

  • alvian on 30/09/2025 - 14:42

    Is it safe to avoid adjusting the gap myself, or should I do it?

    Yes. Yes. Just lightly tap the plug on a surface and measure with a gauge.

  • Euphemistic on 30/09/2025 - 14:49
    +4

    Adjusting spark plug gaps ised to be a thing that was done as part of a routine service. Especially when spark plugs needed replacing far more regularly. It is conpletely normal to have to adjust them.

  • jv on 30/09/2025 - 15:17
    -1

    tap tap tap…

  • bigticket on 30/09/2025 - 16:00
    +1

    If you tap tap tap too far and need open the gap slightly, lever from the threaded body of the plug not the center electrode to prevent cracking the ceramic.

  • Muppet Detector on 30/09/2025 - 16:08
    -1

    I have a Honda lawn mower HRN216VKUA.

    Is it a ride on mower?

    Automotive, really?

  • brendanm on 30/09/2025 - 16:41
    +3

    Jeeze Louise, give it a light tap on the bench and it will be at spec. Very much overthinking this.

  • MS Paint on 30/09/2025 - 16:46
    +2

    It's a lawn mower. K.I.S.S

    Was hopping to avoid manually changing it.

    Where are you hopping to? I'm confused.

    • DashCam AKA Rolts on 30/09/2025 - 17:26
      +5

      Asked Uncle Ian to gap a lawnmower plug for me once. He chucked it at me 'ead. Missed and bounced off the shed wall. When I checked it with a feeler gauge, it was spot on. The man's a legend.

      • MS Paint on 30/09/2025 - 20:09
        +1

        Uncle Ian makes scents. Cheers

      • pegaxs on 30/09/2025 - 22:27
        +2

        I’ve heard he just uses the top lip of his Tally-Ho papers box to gap plugs… That is when he isn’t just gapping them by eye…

    • Muppet Detector on 02/10/2025 - 16:10

      Where are you hopping to?

      On the spot.

      Sort of like running on the spot but you only use one foot.

  • pegaxs on 30/09/2025 - 18:21
    +4

    48mm…

    Literally over thinking it. It’s a mower. Whatever the new plug falls out of the box with, run it.

    Also lol @ CBF “manually adjusting” a plug gap 0.1mm.. oh, the pain.

  • Ocker on 30/09/2025 - 18:53
    +1

    Old timers would not need to ask such a question, it was all part of growing up doing the majority of car maintenance yourself.

    • JIMB0 on 30/09/2025 - 20:39

      Young people these days are gob smacked when they find out you service your own car, change your own tap washers etc.

      • tenpercent on 30/09/2025 - 23:11
        +1

        The missus changes the tap washers. They're freshly laundered and folded twice a week. Hang 'em on the tap after a shower.

      • Muppet Detector on 02/10/2025 - 16:13

        Young people these days are gobsmacked that anybody needs to do these things, far less that anybody (including themselves) actually needs to.

        "Engine light on"

        "Awesome, that bit is working"

  • saltypete on 30/09/2025 - 22:37
    +1

    That model spark plug is likely used for multiple different engines. Just get a feeler guage and gap it accoding to your mower specs.

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