Which plugs for high octane fuel?

steviecops

Chief Petty Officer
Joined
Oct 3, 2003
Messages
585
I have a 1980 Johnson 55. I have learned from this board, that it is designed to run on 87 octane unleaded, with champion spark plugs.<br /><br />The trouble is, over here in the U.K, we can only buy 95 octane unleaded.<br /><br />Will using the higher octane hurt my engine? And should I change to a different spark plug, or stick with the champions which are recommended?<br /><br />Thanks in advance.<br /><br />Steve
 

jim dozier

Lieutenant Commander
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Jan 8, 2003
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1,970
Re: Which plugs for high octane fuel?

Be advised that there are different ways to calculate octane in different parts of the world. Currently in the USA, if you look at the pumps you will see an octane sticker that says <br />(R + M)/2 which is the average of 2 different methods; R (Research method) and M (Motor Octane Method) for calculating octane. When I was a kid in the 60's Sunoco used to offer 103 octane and most high octanes were listed at around 100 octane. Then they changed in the 70's to the method above and they all dropped into the low 90's or upper 80's. So you need to know the method used or you may be comparing apples and oranges. I am pretty sure that the 95 octane in your country is not the same as the 95 (which we don't even have) in the USA.
 

JB

Honorary Moderator Emeritus
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Mar 25, 2001
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45,907
Re: Which plugs for high octane fuel?

Hi, Stevie.<br /><br />I agree with Jim.<br /><br />I believe that unleaded regular (87 octane in the USA) is rated at 91 octane in the UK, but it could be 95.<br /><br />The fuel you use should not affect the proper choice of spark plugs. Stick with the recommended Champions.<br /><br />Good luck. :)
 

steviecops

Chief Petty Officer
Joined
Oct 3, 2003
Messages
585
Re: Which plugs for high octane fuel?

Thanks JimD and JB.<br /><br />I didn't know that octane ratings differed in different countries. I learn something new every time ai look at this web site ;o)<br /><br />As 95 seems to be the standard octane rating on all our unleaded, it must be the same as your standard 87.<br /><br />Thanks again guys.<br /><br />P.S. Ignore all the anti American demonstrators that you see on the TV this week. They are a small minority of the British public.<br /><br />All the best<br />Steve
 

JB

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Re: Which plugs for high octane fuel?

Thanks, Steviecops.<br /><br />I guess the UK is like the USA that way. 5% of the people make 90% of the noise.
 

nordy

Petty Officer 2nd Class
Joined
Aug 13, 2003
Messages
117
Re: Which plugs for high octane fuel?

Hello Steviecops,<br /><br />higher octane fuel in no way can damage your engine.<br />That was your question.<br />It even will reduce the possibility of dangerous detonation in your engine.<br />So be happy to have better 95 RON fuel in Britain.<br /><br />Nordy
 

steviecops

Chief Petty Officer
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Oct 3, 2003
Messages
585
Re: Which plugs for high octane fuel?

Thanks Nordy, I'm glad to hear that it is safe to use ;o)
 
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