What type of gas?

[bnk999]

Just curious what octane y'all run in your Chrysler/Force motors? <br />I have always ran regular 87 octane with no problems, but was wondering if switching to premium would yield any advantages i.e. less carbon build up, more power etc, <br />Or if there were any downsides to running premium especially in the older motors?

 

[eurolarva]

Re: What type of gas?

87 octane is fine. The only problem with 87 octane is that it is hard to find without ethonal. Even though I tried high octane on my chyrsler and it would not run worth a crap. Went back to 87 and it ran fine.

 

[jrem123]

Re: What type of gas?

I ran 87 for several seasons, but switched to 89 octane. The engine starts much easier when warm on the better gas, that's the only performance difference. I had to crank it over and over on the 89 to get it to go when hot . . .

 

[JB]

Re: What type of gas?

89 is not better gas, jrem. It is poorer.<br /><br />Whatever your problem was, it was not using the recommended fuel.

 

[jrem123]

Re: What type of gas?

hmm, a) higher octane = higher cost = slower burn = poorer gas? and b) Force recommends a certain grade of fuel for their outboards?

 

[JB]

Re: What type of gas?

Higher octane simply means more knock resistant in high compression engines, jrem. In low compression engines (virtually any non-racing 2 stroke) unleaded regular is superior to gas that has deposit creating additives.<br /><br />The extra cost is for additives that 2 strokes do not need or like.<br /><br />The myth about "premium" gas being superior was created by marketeers in the days when tetraethyl lead was a legal additive (it lubricated valve stems) and high compression in auto engines was becoming common. <br /><br />Even in those days most outboard makers recommended "white" gas for outboards because it had no lead and produced lower coking and other deposits. "White" gas was about 80 octane and contained no additives at all. Check the requirements on Coleman gasoline lanterns; "do not use gas with additives, use "white" gas only". The mantles were good for only a very few hours burning gas with additives before they coked up with deposits and had to be replaced.<br /><br />The additives in premium gas are not performance enhancing, they are knock prevention which is ONLY useful in high compression 4 stroke engines. In 2 stroke engines they are performance reducing and deposit producing.

 

[jasonbailey]

Re: What type of gas?

Thanks for the info JB. After a long day at work that made sense. 87 Octane for me...

 

[jrem123]

Re: What type of gas?

hmm, okay, that makes sense, I am familiar with Colman white gas from my boy scout camping days.<br /><br />I guess I'll go back to the "less expensive" gas and see how it runs now that I've discovered Seafoam.