Fouled Plugs

[Bob Grieb]

I installed the new jet (.032) this weekend and the engine started and ran for a while at idle without a problem. Time will tell if if they will foul.

Good to hear from you Donny.

Bob

[Don McCombs]

Don, is the AB-2 hotter or colder than the AB-6 and how many steps in between

Donny,

I'm not disputing whether the AB-6 works or not. Bob asked for a cross-reference. While searching for an answer to his question, I discovered that the cross-references, that I could find, didn't list the AB-6 as a cross to the D-21, but did list the AB-2. I also searched for a chart that would show the relative heat ranges of the various plugs. I came up dry on that one. But, I did not conduct an exhaustive search, either. Also, please bear in mind, that my initial response was to a member whose Cub, like mine, does not see heavy use. Bottom line is...if the AB-6 works well in your particular application without fouling, use it.

[Jim Becker]

Here is some useful informaton on heat ranges on the NGK site:
http://www.ngksparkplugs.com/techinfo/s ... chtips.asp
They didn't seen to have their own symbol code chart, but here is one somebody else has posted:
http://www.sparkplugs.co.uk/pages/techn ... g-code.htm
It looks like 2 is their hottest plug, 6 is mid-range. That would lead me to believe that a 6 is adequate and 2 is hotter than needed. Unless you run the tractor heavily, you can probably use it with no problem. Champion ranges run from 1 to 25. My guess is that the D-21 is probably somewhere between NGK's 6 and 2, but direct comparisons between brands tend to only be semi-valid.

[Bob Grieb]

Hi Jim

Thanks for the information. I have filed that away for future reference as I have a tendency to foget what I learn.

Bob