I just bought a used snapper rear engine rider, it beats pushing, and the plug is black. It is a champion j19lm. Its is a 8hp 30"cut briggs. What other plug would you use and why? I know that champion are bottom of the line plugs so I need something that will stand up to everyday use. Yes I know the mower is not commerical but I have been pushing yards way to long. Thanks in Advanced!