When I went looking for new shielded spark plugs for my Onan 6.5 MCCK marine genset, I was greeted with a variety of "nope - never saw anything like that" and "Uh oh - they're awful expensive" responses. Finally, on the advice of a marine mechanic, I tried Part Source. Issue solved - plug is a Champion XMJ20 and commonly available. I paid 14.99 each - I've seen them for less (in US); I've seen them for more (both US and Canada).
