best spark plug and why

Mon Jul 22, 2013 7:54 pm

During our recent manifest, Raymond and Tezell made a big fuss about my spark plugs in my Cubs being a little rusty and possibly not operating at a high rate of efficiency. So to satisfy them, I thought I would change out some of them. I need some recommendations and reasons for your choices. Maybe yours burns hotter, lasts longer, or whatever. Thanks for your response..

Billy Ray

Re: best spark plug and why

Mon Jul 22, 2013 7:59 pm

D21s last forever for me, I run D15s in the working cubs :wink: and under $2 each :lol:

Re: best spark plug and why

Mon Jul 22, 2013 8:05 pm

Auto-Lite BT-10, because I have 2 N.O.S. boxes from the mid-1950's and that is also what the parts manual says should be used.

Re: best spark plug and why

Mon Jul 22, 2013 8:08 pm

I can understand that $2 logic, boss.

Re: best spark plug and why

Mon Jul 22, 2013 8:10 pm

brichter wrote:I thought I would change out some of them.

Do you mean all the plugs on some of your Cubs, or some of the plugs on one of your Cubs? If you mean the latter, which plugs will you change? :D

Re: best spark plug and why

Mon Jul 22, 2013 8:15 pm

well, no matter, you didn't give me the benefit of your vast knowledge and experience, Bill. I thought I would start off by changing out #2 on all of them and go from there.

Re: best spark plug and why

Mon Jul 22, 2013 8:16 pm

brichter wrote:well, no matter, you didn't give me the benefit of your vast knowledge and experience, Bill. I thought I would start off by changing out #2 on all of them and go from there.

#2 is an excellent choice to begin with.

Re: best spark plug and why

Mon Jul 22, 2013 9:17 pm

Champion D-21's. Because I said so. :D

Re: best spark plug and why

Mon Jul 22, 2013 9:19 pm

I've been running the same set of D21's since 2007, mowing grass 10 of 12 months, and no issues yet.

Re: best spark plug and why

Mon Jul 22, 2013 10:34 pm

386's or 3116's work well for me.

I think I remember we put 386's in your cub Friday. :D

Re: best spark plug and why

Mon Jul 22, 2013 10:43 pm

Billy Ray:

Champion D-21's as recommended by my former CaseIH Dealer. Looked in the '47 Owner's Manual and Champion 15-A were the recommended plugs. They seem to cross to an AutoLite 386. Those cross to Champion D-16's Those are too cold for my liking and my Cubs don't run well on them. I like the D-21's .. very good plug and I am on the same set I put in back in 2003 or 2004. If you are using your Cub everyday allday then maybe the D-16's are the better choice.

Re: best spark plug and why

Tue Jul 23, 2013 4:51 am

Just bought a tune-up kit...It had Auto Lite plugs in it.....Made in Mexico...Now instead of idling smoothly , it goes barumba, barumba....

Re: best spark plug and why

Tue Jul 23, 2013 8:02 pm

If carbon builds up on the business end of your plugs, causing poor running, you need hotter plugs to burn off the carbon. Champion D21 plugs did the job for me. Plugs burn hotter because there is less insulation around the tip.

Re: best spark plug and why

Tue Jul 23, 2013 8:06 pm

Don McCombs wrote:Champion D-21's. Because I said so. :D

I like your answer Don! :-) and I concur

Re: best spark plug and why

Tue Jul 23, 2013 8:13 pm

pickerandsinger wrote:Just bought a tune-up kit...It had Auto Lite plugs in it.....Made in Mexico...Now instead of idling smoothly , it goes barumba, barumba....

The problem with those plugs is your Cub could run cold today, but hot tamale.