zeedubbya 18 #1 Posted August 12, 2012 I've been doing a little research on here on spark plugs, and it seems there is differing opinions as to the best brand. However, I've run across an issue I can't find the answer to. Why in some of the Onan applications (like Case and John Deere) do they recommend a different spark plug? Wheel Horse manual recommends a Champion RC14YC or equivalent, and John Deere and Case recommend the RS17YX for the Onan lineup. What gives? I know one is a "hotter plug," but is they're really a difference? Just insomniacs curiousity more than anything! Thanks. Share this post Link to post Share on other sites
Tankman 3,515 #2 Posted August 12, 2012 I use the engine manufacturers spec's. Always worked for me. Share this post Link to post Share on other sites
rick 217 #3 Posted August 12, 2012 R means resistor, C stands for 14mm 3/4 inch reach, while S denotes 14mm tapered seat .708 inch reach. We have two completely different plugs already-X denotes fine wire electrode. Why the difference? Cummins/Onan knows, I don't have enough experience with Onan engines to say. I'll wager someone here on the forum knows..... Share this post Link to post Share on other sites
