NGK (6341 BKR5EIX Iridium IX Spark Plug, Pack of 1

Fixing up an old TB200 mower from 2014. This plug was only slightly more expensive than the oem copper one. Iridium is the best of the best for spark plug material. This one worked perfectly out of the box. Don't use a spacer on platinum or Iridium plugs, it wears off the thin layer of Iridium, which turns it back into a cheap copper plug. The spark is much more intense, so spacing isn't needed anyway vs old copper style.

RC12YC replacement in 18hp Kohler. Smooth idle, quick start and running strong.

I have a Troy-Bilt TB110 lawnmower with Briggs & Stratton 550ex motor that I got not running for free. Cleaned out the carburetor and runs good now. I saw the original copper spark plug was oil fouled and did some research and saw this as a replacement for that Champion plug. Threaded right in, motor starts good on first pull and sounds good. Great upgrade to iridium on a small engine.

I was previously using RC12YC champion plugs in the Vanguard engine in my UTV. Unfortunately, I was recently having issues with misfires using these plugs. Changed to the BKR5EIX plugs and the misfiring issues went away. Throttle response is slightly improved as well, which is another benefit.

The order came in a timely manner and the product works as advertised. I was hoping for more performance but at the end of the day it's a Scion XB. LOL

It was time to replace the plugs on my wife's car (an '06 Scion xB); her mileage was dropping, and inspection of the old OEM copper plugs showed sizeable wear and comically large spark gaps.After poking around at options that fit her car, I ended up choosing NGK's Iridium plugs. Granted they're a bit more expensive than the OEM-spec copper plugs (NGK's BKR5ES or the Denso equivalent); they're actually almost double the price. However, in the grand scheme of things, they're cheap. A set of 4 cost about $30, which is a pittance for something that's central to an engine and for parts that'll last many years. Saving half that by buying copper plugs didn't seem worth it.Out of the box they're gapped to the range Toyota recommends for this particular engine (0.7-0.8mm), which is useful. Installation was no different to any other spark plug on the face of the planet, with no hitches. I used some Permatex Anti-Seize on the threads that I had on hand from a previous order.Unfortunately the new plugs didn't turn her box into a fire-breathing 500hp monster. That's a little disappointing. ;) However, the engine does now idle and run a little smoother. We'll see whether her mileage comes back up to the expected level over the next couple of tanks.I'll probably pull the plugs to see how they've fared after 10,000 miles or so. I'll update this review with whatever I discover at that point.

NGK= Great as always. Literally everything else involving the purchase was terrible and that's me being nice about it

Swapped this out with the old copper core in the leaf vacuum and it fired right up and runs perfect