spark plug interchange

[mrrn]

I have a 57' johnson 7.5hp which calls for champ J6C. I wanted a hotter plug and found champ RJ6C as an hotter alternative. Also, an Arnold e3 e3.1 as an interchange. These are lifetime non-fouling at about $7 apiece.
has anyone had any experiance with these plugs?? (e3), and will it ruin anything??

 

[bigtwin]

Re: spark plug interchange

I use them in my ice auger, and my string trimmer, both have 2 stroke motors, and both were very hard to start. The e3 plugs made a huge difference in starting. They also idle better when cold. I wish they made them for my outboard.

 

[Scaaty]

Re: spark plug interchange

Who sells the "Arnold"..? Sounds good..??

 

[bigtwin]

Re: spark plug interchange

I got my e3 plugs at Checker automotive, about $6.00 ea.
Someone told me about them while icefishing, and I couldn't get my power auger running.
The next day I went out and bought a plug, now it starts in 2-3 pulls not 20-30 pulls like it did prior to installing the e3 plug.
worth every ?

 

[F_R]

Re: spark plug interchange

An RJ6C is not a hotter alternative. It is a resistor ("R") plug. Very poor choice because it requires a higher voltage spark to fire across the resistance.

You shouldn't be needing hotter plugs anyway unless you are doing a lot of trolling in cold water. J8C is the next hotter plug than a J6C.

 

[JB]

Re: spark plug interchange

If your engine is really a 1957. . .AD-11. . .the correct plug is not a J6C, it is a J4C.

The hotter J6C is okay for lots of low speed/ trolling operation, but use a J4C for general and high speed use.

Going to hotter than recommended plugs is a poor compensation for magnetos that may not be performing as intended.

 

[jaxflg8r]

Re: spark plug interchange

The Champion plugs website recommends either the J8C or the RJ8C for the 1957 7.5 hp Johnson.

I have the '57 7.5 hp as well, and have used the J6C.......

 

[F_R]

Re: spark plug interchange

See, that's the problem I have with Champion's plug charts. They will reccommend anything that fits the hole. Not only are they saying to use the J8, which is incorrect, they are saying to use the "R" resistor plug which is totally wrong.

 

[mrrn]

Re: spark plug interchange

just replaced both coils on my AD-11 and am running j6c in it.still seems to not rev up as I believe it should. maybe will try j4c as suggested by JB.

 

[mrrn]

Re: spark plug interchange

so.... the J4C foul out quicker at trolling speeds but not at higher RPM's. and my AD-11 was supposed to have the J4C originally. since I have just replaced the coils would switching to the 4's improve operation?? it has 6's in it now and seems ok at low and higher speeds, just not super. I feel that it could be better...

 

[mrrn]

Re: spark plug interchange

the e3 interchanges with the NGK replacment of champs j6c, so making that jump from the champ to e3 seemed logical. but I have not used them before