View Full Version : Gasoline Octane Level

08-27-2004, 06:09 PM
Dad and I just bought an 04 Prostar 197. While Reading the owners manual, we noticed that it said that you should use minimum 89 octane fuel for the boat. I was wondering if any of you guys use under 89 octane fuel, and if it has affected your boat in any negative ways?

08-27-2004, 06:15 PM

I use the high test 92/93 or whatever it is. But I have an older boat. BTW nice looking 197 :headbang: .

And welcome aboard:toast:

08-27-2004, 06:46 PM
Use of fuel with an octane level less than recommended will lead to spark knock. The knock sensor will pick up on this and retard the timing...the engine will then make less power. This is all in an effort to keep the spark knock (AKA detonation) from destroying the engine.