My 91 440 Prowler calls for a BR9ES NGK plug. My understanding is that the BR9ES and The BR9EYA are interchangeable plugs. The EYA has a grooved tip that is supposed to reduce plug fouling. My question is does anyone here have first hand experience with the EYA plugs and did they find them better than the standard ES plug.
I had a 90 Prowler and tried the EYA in that sled to keep the plugs from fouling. They fouled just as much as the ES ones did. I tried a few others, too. I finally adjusted the oil pump and plug fouling went to pretty much zero, even with the ES plugs. I still carried 4 spares, though
2007 Dragon RMK 700 155", 2008 RMK 600 155", 95 Prowler 550 2-up, Really OLD AC Cheetah
I use Iridium BR9EIX plugs and they don't foul nearly as much. More expensive though.
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