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Spark Plug Confusion

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Sam110

Regular Contributor
My '85 Evinrude 90 V4 model E90TLCOS calls for Champion QL77J4 or L77J4 plugs. I found several used plugs the previous owner had evidently used which were QL77J4C. So while at my local auto parts store I inquired if they carried the QL77J4 or ----J4C plugs. They had plenty QL77JC4's but being unsure of the difference I passed and decided to look them up in my service manual to verify I had the correct plug number. I checked here on Marine Engine and they list a Champion QL16V ? So now I'm confused. Googling Champion's cross reference chart they list the QL77JC4 as an equivalent to the plug the manual calls for (QL77J4). So which plug is the preferred plug to use? Can someone shed some light this way please?
 
The "C: indicates a copper electrode for long life. Stick with the Champion QL77JC4 plugs, gaping them at either:
.040 for a super hot spark... or... .030 for a longer life.
 
Sam110 said:
My '85 Evinrude 90 V4 model E90TLCOS calls for Champion QL77J4 or L77J4 plugs. I found several used plugs the previous owner had evidently used which were QL77J4C. So while at my local auto parts store I inquired if they carried the QL77J4 or ----J4C plugs. They had plenty QL77JC4's but being unsure of the difference I passed and decided to look them up in my service manual to verify I had the correct plug number. I checked here on Marine Engine and they list a Champion QL16V ? So now I'm confused. Googling Champion's cross reference chart they list the QL77JC4 as an equivalent to the plug the manual calls for (QL77J4). So which plug is the preferred plug to use? Can someone shed some light this way please?
Click to expand...

I think you will find that QL77J4 are obsolete

QL77JC4 are the replacement and preferred type. 0.030" is now the recommended gap

QL82C are an alternative

I dont know where you found QL16V listed for your engine They are surface gap plugs
 
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