Yamaha 15 horse 4 stroke outboard sparkplug

[Bofire]

I went and got a new plug, the standard plug per the book is a DPR6EB-9, they gave me a champion plug. The new plug is a 5/8 size, the plug that is in the motor is bigger than 5/8. What size is it? slightly larger than 5/8 do they make metric plugs?
thanks
Carl

[Bofire]

Those charts show no replacement, it still does not work with a 5/8 plug socket, the replacement one does? any way, I got rid of the bad gas, put in new, cleaned the sediment bowl. Got it to start and idle a bit, kept doing it, eventually got it to idle and now runs great, GREAT!!!!! Now I need to find out about the spark plug and what socket it takes.
Carl

[branches]

The size might be 13/16 that is what my plugs are for my 25 horse.

[Grit dog]

Vast majority of plugs are 5/8 or 13/16, even on every metric, European or Japanese engine I've had, but there are also 3/4 and 18mm socket sizes. Not sure I've seen one before.

[luckyman]

My Honda motor cycle has a weird size plug also. 5/8, 3/4 & 13/16 wont fit.
 I'll have to find a 18mm plug socket and see if it fits.

[birddogdad]

call the tech team at boats.net       i have had great success there and prices are good for all oem stuff

[Alchase]

The NGK DPR6EB-9s are available on Amazon

https://www.amazon.com/NGK-DPR6EB-9-Standard-Spark-Plug/dp/B001RM8AFC/ref=sr_1_1?s=automotive&ie=UTF8&qid=1536168017&sr=1-1&keywords=DPR6EB-9

[Bofire]

NGK sight says it is "5/8 (16mm)" , I had bad gas in it, got fresh gas in, pulled it over about a 100 times, got it to sputter, more and more, then it took off and ran fine!!! I am going in to town to the Boat store and look into this plug thing.
Thanks