Which fuel to use for '79 evinrude 35hp?

[fishon1213]

Which fuel should I be using for my '79 evinrude, its a 35hp. Our gas stations here usually have 87, 89, and 93 octanes. The 89 is 10% ethanol.

All of my fuel lines have been replaced and my carb has been rebuilt with a new float. Is there any other dangers of ethanol?

I do get a spark knock from time to time. Should I run a higher octane to fix this?

 

[Joe Reeves]

Re: Which fuel to use for '79 evinrude 35hp?

That engine is designed to run properly on 87 octane gasoline.

The knock question pertaining to octane I will leave to another member.

 

[JB]

Re: Which fuel to use for '79 evinrude 35hp?

I really doubt that what sounds like a spark knock is really that. Must be something else.

 

[DJ]

Re: Which fuel to use for '79 evinrude 35hp?

87 octane is more than adequate. If you are truly getting "detonation" you have other issues, such as carbon build up.

In that case, do a "de-carb". See link below.

http://forums.iboats.com/showthread.php?p=2648076#post2648076