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Really Strange Spark Plug Issues!!

MittyB

Member
Engine was running and that but i thought it was time to replace spark plugs so i bought the exact same ones and now it will start on the new ones when i run it on the old ones and warm it up but from a cold start the new plugs will not start but there is a spark so very strange
 
Engine was running and that but i thought it was time to replace spark plugs so i bought the exact same ones and now it will start on the new ones when i run it on the old ones and warm it up but from a cold start the new plugs will not start but there is a spark so very strange

You dont say what engine or what plugs you are using.
However you have started 6 or 7 threads in the last 3 months about a 1982 Evinrude 60 HP presumably that's the one (E60TLCNM)?

The recommended plugs are Champion QL77JC4 gapped at 0.030" or , for sustained high speed use only , surface gap L78V

You mention in one earlier post having NGK BR9HS-10 in it ......... These are resistor plugs ... you should not be using resistor plugs in this engine. They are often listed as equivalents of QL77JC4 but they are not. They could be causing some of your problems

The "Q" series Champion plugs are inductively suppressed The NGK equivalents are indicated by a "Z" in the number. If you use NGK plugs use BZ9HS-10 or the un-suppressed B9HS or B9HS-10

NGK grade 9 is a cooler plug than the recommended Champions and I would have suggested a grade 8 or 7 but I notice B9HS-10 are included in the original parts lists

the -10 at the end of NGK numbers indicates that they are supplied gapped at 1.0mm. These will have to be re-gapped to 0.030"
 
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