I have a 1999 225HP OPTI. It has always had PZFR5F-11 plugs in it. My manual calls for this plug. I was told by a mechanic that it should be running another plug Mercury now calls for. That plug is IZFR5G. Which is correct? Or does it matter. Will one get better ignition in a bass boat that runs mostly top end.
You should be running NGK: IZFR5G (gapped at .032"). Ignore information to the contrary.... this has been covered by multiple service bulletins throughout the years.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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Thanks! What is so aggravating is I have had the annual done at two different Mercury shops and neither put the new plug in. BPS in Jackson, MS told me all updates had been done and the same guy that told me about the new plug said when he checked the records, none had been done. He completed the updates and put the new plug in. Looks like I have someone I can trust now.
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