Decided to join the others that run ethanol free gas. SeeWee Outpost has it in premium. Is that OK to run in my engine all the time? I have a 2002 90 HP 2 stroke Mercury. I was also wondering how often I should run seafoam to help prevent carbon build up? Thanks for the help.
The best way to a fisherman’s heart is through his fly.
2002 Florida Skiff
90 Merc.
Normally the engine manuals specify 87 octane gasoline. I’ve heard of premium causing problems with engines. I would strongly suggest verifying it with your repair shop first. Now the seafoam is another thing. I believe it is very helpful, personally, and although I don’t put it in every tankful of gas, I do use it about every 3 or 4 tanks.
Blackwaterkatz
My understanding from growing up in the age of muscle cars: Higher octane means it will resist knock or pre-ignition. In other words it can be compressed more and not ignite from the heat before the spark plug lights it. The higher the compression ratio, the higher octane you need. In a way you could say that high octane fuel is actually less volatile or ignitable. There is no more energy in the high test than the regular. There is nothing wrong with running higher octane than required but no advantage either as long as it doesn’t knock. If there is no other reason (ie no ethanol) it is a waste of money. That being said if it will be stored for a long time and you are afraid it will lose octane rating over time then I would start with a higher octane.
18.5 Baycraft Flats Edition
Johnson 150 Oceanrunner
Wood Driftboat
Thanks for the help. I Chris V. that I was going to run E-free gas but forgot to mention that it was high test. Just want to do what is best. I really appreciate the opinions.
The best way to a fisherman’s heart is through his fly.
2002 Florida Skiff
90 Merc.
Flyvet covered it pretty well. Premium also has more detergents and dispersants to aid in keeping the fuel system and combustion chamber cleaner. I would recommend hi-test for carbed engines. However, the DFI motor computers are programmed for 87 and the way it was explained to me is that under sudden decelleration premium can cause some issues that can harm the engine. Seafoam or PRI-G don’t effect octane rating and will help with reduction in carbon deposits. This applies to two strokes. I wouldn’t expect any negative issues with premium in a four stroke.