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900 spark plug?

1328 Views 6 Replies 4 Participants Last post by  Tractor-Holic
hey gang, just another dumb spark question. i have replaced the coil . and bypassed the points , now i have a good clean spark if i ground the plug wire, when i attache the new plug and ground it out i get intermitant spark at times and no spark at all when cranking . im using a cj8 champion plug brand new. any suggestions?:thanku:
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Not to start a brand war--but I'd toss the Champion plug and try another brand..I have good luck with Autolite plugs,and I wont buy any "miracle" plugs with multiple ground elctrodes or pinpoint center electrodes,99% of them wont even start an engine after they have been used awhile..

I like the fact many "free" mowers are available ,tossed away only because they refused to start with those expensive plugs,and all I need to do to get many running is replace them with a good old fashioned Autolite NON PLATINUM plug like a # 295 or #458 and they usually start right up..

I've had some Champions run forever with no issues,on others, the spark comes and goes when it feels like it on some of them,I find they like to short out up inside the "shell" and the spark jumps way up there,instead of at the electrodes...if you get good consistent spart at the wire using a bolt or screwdriver to hold it 1/4" away from ground,but its intermittent using the plug,then I'd say the spark plug is whats giving you grief...
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The "C" in a CJ-8 stands for "Chainsaw",its got a 3/4" hex instead of 13/16" and a shorter insulator than a "regular" J-8 or J-8C plug has,but its the identical heat range..the J-19LM is a hotter plug and has a slightly shorter insulator,but works well in 95% of all mowers that used a J-8..

I dont mean to bash any particular plug,or praise one brand either,I too have had many of ANY brand that dont fire properly right out of the box,or shortly after installing them...NGK,Bosch,Champion,Nippondenso,even A-C and Autolites and Motocrafts,but the last three I've had the least failures with..

I wont use Bosch platinum plugs ever again,at least not in an older Chevy small block,every time I installed those plugs I had one "dead" cylinder ,it skipped WORSE after the tune up!!--I put the old AC plugs back in,it ran perfectly again..those platinum plugs just dont work in engines that were not designed for them,and came factory with them..

I've had poor luck with any plug that has a "pinpoint" center electrode,or multiple ground electrodes--tried one of those new "E5" super-duper small engine plugs and they SUCK,I had the one I bought foul in about 10 minutes and refused to fire at ANY of the electrodes,instead it fired up inside the shell,just like Champions often do when they fail--I dont know if magnetos higher voltage makes the spark jump right through the porcelain inside the shell or what,but every plug that does that is never going to run an engine right,though it MAY start and run great--sometimes!!--then die again on you
I took the "super" plug back to Lowes and got 2 Champions for less money,and it ran perfect again..(for how long,who knows!)..
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