Re: 35hp Johnson Seahorse carb adjustment
When these engines were built The recommendation was for regular octane(what was available then?) or white marine gasoline,whatever that may be.<br />My recommendation for higher octane (89 is also fine)comes through trial and error.I found that I can use a little bit less oil this way,which means a little bit less water pollution.<br />I do not know if there is any science that supports my theory,but I run my old engines at 1:32 with higher octane gas.Whenever I take one of them apart in my winter puttering games, I see that the bearings are in great shape.<br />America's 87 octane fuel is probably fine for the relatively large sized car engines (3 to 5 liter engines are no exception)In Europe where 1600 cc to 2500 cc engines are the norm ,we find much higher octane fuel and these engines run at a much higher rpm. <br />When I look at the small volume outboard engines and their high rpm (between 4500 and 6500)I cannot help ,but make a comparison with the small european engines,their high rpm and their use of higher octane fuels.<br />There may be science to back this up or debunk it.I dont know.<br />But for now I will stick to my gut feeling on this one.