johnson 18hp spark plugs

[jdsgrog]

Just wanted to make sure, but which plugs should I use for a '58 fd-12? J4C's or J6C's.

 

[Vic.S]

Re: johnson 18hp spark plugs

contiuouswave.com gives J4C.

J6C are just a little hotter. May be useful if you suffer from fouling.

 

[tashasdaddy]

Re: johnson 18hp spark plugs

agree^^^ also opening J4C to .040 will help fouling.

 

[jdsgrog]

Re: johnson 18hp spark plugs

thanks. I didn't see any problem with fouling. The motor came with j6c's, but I saw in the manual that the originals were supposed to be j4j's. I tried the j4c's and it ran fine at mid to higher rpm's. But it was the same with the j6c's. I think i'm going to have to rebuild the carb and clean out the low speed jets. I have a question about carb cleaners, but I'll ask that in another topic.

 

[tashasdaddy]

Re: johnson 18hp spark plugs

read th TOP SECRET FILE.