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top two plugs not firing 1970 50hp

david baker

New member
i ..have a mercury 2stroke 50 hp 1970s outboard. top two plugs are not sparking .i have checked coils .black box. tested wiring.put in new plugs. all working ok. but top 2 still not firing. any ideas.? dave.
 
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Re: top two plugs not firing

are they sparking and just not firing the cylinder or no spark ? if they are sparking and not firing the cylinder you may want to do a compression test and if that is good try spraying a little (note small amount) of carb cleaner in the carb or carbs for those cylinders and see if the start firing if so its in the carb (not getting fuel) if its not sparking probably needs a triger (under the flywheel)
 
Re: top two plugs not firing

thanks for that information. i have now sorted it. it was the second black box i put on. put on another black box and it now runs fine. do you know why my ship to shore radio bleeps and says excessive power when engine is running. radio and everything else runs through fuse box. everything else is ok. thanks
 
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