higher octane gas in older motors????

[albass]

Can it benefit an older motor 91 Johnson Fastrike to run 90 octane gas or more or should 87 be sufficient in the older motors????

 

[ezeke]

Re: higher octane gas in older motors????

This is one place where I am confident the folks at BRP have the correct answers:

http://www.evinrude.com/en-US/About.Us/FAQ/Oil.Fuel.htm

 

[tashasdaddy]

Re: higher octane gas in older motors????

ezeke, never knew that was there. thanks. a 91 is not an older engine. it's just getting broke in.

 

[ezmobee]

Re: higher octane gas in older motors????

I know the guy on maxrules.com is quite adamant against Regular: http://www.maxrules.com/fixgas.html

Agreeing with TD....I have to admit I laughed when I read your title as "older motor" and then read it was a 91. 8)

 

[ezeke]

Re: higher octane gas in older motors????

It serves no one to take things out of context.

I don't see the conflict, BRP says 89 octane preferred,

Further in his article, Bill Kelley says:

"...Should I burn PREMIUM gas?
NO! here's why. The octane ratings are composed of 2 components, research octane and motor octane (RXM/2) divided by 2. The RESEARCH octane is the quality of the base stock, the MOTOR octane is derived from additives. The oil company will never tell you the ratios. Problem is the highest octanes are achieved by MOTOR octane additives, which will just gum up the pistons in a 2 cycle engine. Base stock is generally the same. The MID-GRADE gas has the detergent additives needed to clean your motor and sufficient octane for MOST motors. If you have a MERCURY, FORCE or OMC motor from the early 70's thru mid-80's refer to technical bulletins from the manufacturers for timing changes and replacement head gaskets to lower compression to use today's gasoline."

 

[Scaaty]

Re: higher octane gas in older motors????

WAY too many builders I know DEMAND 89 octane. No 87, no 92-3...and these people I NEVER question. 10-15 cents more a gallon..just do it.

 

[F_R]

Re: higher octane gas in older motors????

Sure is a lot of mis-information and confusion out there isn't there? I'm not even going to touch this one. That's rare, huh?

 

[F_R]

Re: higher octane gas in older motors????

Oops, hope one of the above contributors take my previous comment personally as applying to them. It is not a personal attack, just pointing out the different opinions and viewpoints.