Dball 12 #1 Posted August 30, 2016 Not sure if this is the correct place to post this but what size plug came with the onan motor if you have changed it what have u found to be best and y thank you for any and all help I do not have a manual for mine some I'm winging it on some things Share this post Link to post Share on other sites
squonk 42,247 #2 Posted August 30, 2016 I use Autolite 104 Share this post Link to post Share on other sites
DougC 2,642 #3 Posted August 30, 2016 If you like a Champion spark plug a RS17YX is the number. That being said. I offer this as another choice and would never intend to say Champion is better or worse than Autolite. I am an AC Delco guy, but use another brand in my 's cause I've never taken the time to see what spark pug crosses over to AC. Share this post Link to post Share on other sites
Kurt-NEPA 755 #4 Posted August 30, 2016 +1 on the Champion RS17YX . Both my 520H's are running them. I've tried other, but these run the best. 1 Share this post Link to post Share on other sites
Dball 12 #5 Posted August 30, 2016 What I have found on the net is mixed stuff on plugs what I found was champion rc14yc I then some say run the 17 so not sure which would be best never owned anything that used the onan motor I was thinking of getting the A/C Delco platinum plugs just unsure what size Share this post Link to post Share on other sites
Kurt-NEPA 755 #6 Posted August 30, 2016 Wheel Horse (Toro) originally specified the RC14YC plug. Later they issued a technical bulletin changing that to RS17YX. Many of us think that was to accommodate 10% Ethanol fuel. I've used both plugs, Both work, but the 17 plug seem to work better - smoother operation. Both my 520H's start up and run perfectly on the 17 plug. (I do have electric fuel pumps, I highly recommend them). Share this post Link to post Share on other sites
