Too many NGK ZFR5F spark plugs

[HotTommy]

I'm ready to replace the spark plugs in my 2016 Mercury 115 four stroke. The factory plugs in it are marked NGK ZFR5F. Looking online I see several different plugs that include those numbers. The most common are ZFR5F-11. I've also seen a ZFR5F/7558. So what should I be looking for? Does it matter which one I choose?

 

[Sea Rider]

The most common plug with 11 ending means it's factory gaped to 1.1 mm. If your outboard uses a different gap will need to adjust the actual gap to that ? given gap...

Happy Boating

 

[racerone]

Many times sparkplugs are replaced for no good reason.-----Sparkplugs in many pick up trucks are in the engine for 10 years.-----150,000 miles or so.-----Not sure why you would replace them after 100 hrs.

 

[HotTommy]

Searider - Thanks for the info.
racerone - On an earlier thread I asked for advice on when to change plugs. The answers varied but several suggested every year. I think thats too often on a 4-stroke, but I decided to stockpile some plugs just in case.

 

[Faztbullet]

You don't need the -11 plugs as they are different than the originals .The 7558 is the part number of the plug, so call your nearest Autozone and ask if they have the 7558 plugs in stock.

 

[HotTommy]

By my math there are about 100 million five character combinations NGK could have used for any of its lines of spark plugs. So my rhetorical question is, why the heck didn't they use different numbers if the spark plugs were going to be different from each other? And why did Mercury specify a spark plug without specifying which specific sub type to use? I'm not impressed by either company.