The electrical charge will take the path of least resistance and jump to only one of the ground electrodes. The principal advantage of multiple ground plugs is, as one electrode erodes the charge will jump to the narrowest gap available. The plug will,therefore,last longer.
Toyota uses multiple ground plugs in their vehicles. I recently changed some in a Camry at 76,000 miles that had barely measureable erosion of the gap.

One E3 costs as much as three Champion CJ8 plugs (which is typical for small engine).

If you read the fine print on the E3 they will replace it for you one time only, as long as you mail back the plug with the original cash register receipt. They will not keep sending you replacements for the life of the engine. It is a one time free replacement.

So for your eight bucks you will get (at most) two of the E3 plugs. If two of the E3 plugs last longer than three Champion plugs you are ahead of the game. Assuming you can hold onto the cash register receipt for that long.

I once bought those "Triple Edge" wiper blades with the free lifetime replacement guarantee! Their S&H "fee" was $3 more than I paid for the blades at the local store.

Freeze dried water for sale -- just add water, and stir.

Whatever, the plugs are great, and I expect it will be the last plug you put into any piece of equipment. It's not snake oil or just another platinum plug. By the way, I use snake oil, too! Make it myself.

I like "snake oil" saxman, "voodoo brand oil" is almost as good! Hey, sounds like I might have the same ol' Crapsman/Ryobi trimmer your have about the same age. My brother bought it brand new and didn't like it so I traded a used McCulloch for it. Question. The darn bump head NEVER did feed right from day one. Switching from round to octangular cut line for better cutting performance probably didn't help much either. I've put up with it for many years now because that little 31cc engine still runs great has lots of power! Hmmmm? Wonder if my "snake oil" had anything to do with that? Anywho, I recently scored a "Grass Gator Head" for it off ebay and hope it will perform like it should, even with aftermarket line. Are you still running the factory spool or aftermarket?

Uuuh, yeah, right up there with miracle caburetors, hydrogen injection and gasoline milage elixirs. Hope they didn't cost any more than a regular champion mower plug.

echoman; yes, still using the factory spool. Mine's not a Craftsman, just a Ryobi 725r. The bump cap is worn out and needs replacing but it always has taken a few bumps to make it feed. I use the twin packs of standard .090 line and rewind it by putting the new line in each side and counter-winding the spool.

Ryobi at the time, and for several years made units with the Craftsman name,MTD,and Troy Bilt, etc. I figured the spools were almost identical as the curved and straight shafts were I believe. How do you tie the lines if you "split" 2 pieces? Tie a knot in both ends as you feed it through each hole and wrap the opposite way? Would make sense that it would feed better, rather than wrapping it per the manus instructions. It always gets tangled and knotted even when spraying with silicone or oil lube sprays. Nothing has seemed to work well for me with this particular spool design.

Use two 10' pieces of line. You line up the arrows, insert the line and push it through until it comes up out of the spool, then bend the end down and stick it in a hole for that purpose. Repeat on the other side, then wind the line onto the spool.
I went back to Home depot this afternoon and got an E3 plug for the Ryobi - it makes a lot of difference. I've learned something with these plugs - an engine can run okay but the plug can still be marginal. I'll never again let plugs run year in and year out like I've always done (except for the E3s, of course). From now on I'm replacing the regular plugs every couple of years regardless of how good the engines run. When I pulled the 12 year old plug, it looked very good - no carbon build-up or obvious electrode wear. It did look a little close, and I couldn't get my .025" gauge in it. I opened it to .030", put it back in and it ran worse. That was all I needed to make me go get a new plug. The Ryobi was running great with the trimmer head, but with the blower head it had dropped a lot of RPM compared to a couple years ago (takes a lot of power). Sounds like it picked up a couple hundred more with the E3 and throttle response is now instant.

Looks interesting. I clicked through the website to Amazon and they sale the different plugs for 6.99 each with free ship (orders of 25.00). They seem to have a good price on Sta-Bil too

Skip

I've eyed those E-3's, but never wanted to pay that much. Sax, do they make starting easier too? I may pick one up. What part# on the plug for the Ryobi? This engine has always been cold natured in starting but runs well and makes good power once running. Always starts warm with 1 pull. I did cut the plastic needle limiters off years ago when I put a kit in the carb thinking there may have been a problem there. I know the carb is tuned, just a finicky engine when cold.

E3.16 for the Ryobi 725r. They have a cross-reference page on the site. Starting is easier but still finicky - I haven't cut the limiter caps on mine but I'm sure I need to enrich the low-speed side for faster starts. The old B&S engine took a E3.12.

Try the Champion "Easystart" ,you will have to check the # probably 5843. Works extremely well an under $3 here at Home Depot.