Non-oxygenated gas (ethanol free)

[mjc3834merc]

Bought my boat last spring. It has a 1989 35hp Merc two stroke on it. I wanted to do the best I could for the motor (runs great) so I read everything I could. It seems, for a number of reasons, ethanol is NOT real good for my motor. Not a problem. I can still buy non-oxygenated gas here in Minnesota and thats what I've been running in my motor. Now, in another thread, a guy with a fuel problem asks about running 91 octane and JB says

" 87 octane regular is what you need to use.

The notion that "premium" fuel is higher quality than regular is a myth. It is more likely to harm your engine than help."

Ok...ethanol bad....non-oxygenated gas good....non-oxygenated gas only comes in 91 octane......91 octane bad (?). You guys have helped me a lot but sometimes you drive me nuts trying to keep up with you.

Would love to hear what you guys use in your older motors. And anything else you'd like to throw in about this subject.
Mike C

 

[j_martin]

Re: Non-oxygenated gas (ethanol free)

Bought my boat last spring. It has a 1989 35hp Merc two stroke on it. I wanted to do the best I could for the motor (runs great) so I read everything I could. It seems, for a number of reasons, ethanol is NOT real good for my motor. Not a problem. I can still buy non-oxygenated gas here in Minnesota and thats what I've been running in my motor. Now, in another thread, a guy with a fuel problem asks about running 91 octane and JB says

" 87 octane regular is what you need to use.

The notion that "premium" fuel is higher quality than regular is a myth. It is more likely to harm your engine than help."

Ok...ethanol bad....non-oxygenated gas good....non-oxygenated gas only comes in 91 octane......91 octane bad (?). You guys have helped me a lot but sometimes you drive me nuts trying to keep up with you.

Would love to hear what you guys use in your older motors. And anything else you'd like to throw in about this subject.
Mike C

Octane has to do with the tendency to knock, or pre-ignite. Higher octane does not improve the performance of a particular motor unless the motor is modified to use the fuel's full capabilities, usually by raising the compression.

For your purposes, it's a non issue, especially that small a difference in octane. However, not having the detrimental effects of alcohol in the fuel, especially in a marine environment more than makes up for the increased cost.

91 NO is all I run in my XR4. When I got it, it had about 10 fuel issues, over half caused by ethanol. In the 3 years I've owned it, I've put in one fuel pump kit, and it didn't need it. I've ditched the advance timing module and run full advance of 23 degrees at mid throttle. The additional octane makes it run real sweet at that, where 87 would "rattle" a bit.

Since I've gone to NO in my small engines, I now have chain saws wear out their gaskets before anything else goes bad. I've almost forgotten how to put a carb kit in a small engine.

Oh, and against the advice of some, I run PenZoil full synthetic in the XR4.

hope it helps
john

 

[trendsetter240]

Re: Non-oxygenated gas (ethanol free)

Bought my boat last spring. It has a 1989 35hp Merc two stroke on it. I wanted to do the best I could for the motor (runs great) so I read everything I could. It seems, for a number of reasons, ethanol is NOT real good for my motor. Not a problem. I can still buy non-oxygenated gas here in Minnesota and thats what I've been running in my motor. Now, in another thread, a guy with a fuel problem asks about running 91 octane and JB says

" 87 octane regular is what you need to use.

The notion that "premium" fuel is higher quality than regular is a myth. It is more likely to harm your engine than help."

Ok...ethanol bad....non-oxygenated gas good....non-oxygenated gas only comes in 91 octane......91 octane bad (?). You guys have helped me a lot but sometimes you drive me nuts trying to keep up with you.

Would love to hear what you guys use in your older motors. And anything else you'd like to throw in about this subject.
Mike C

I run 91 octane ethanol free gas in my outboards. Not for the octane but for that fact that it's ethanol free.

We have the same as you, only ethanol free gas here is 91 or 94 octane. I have run the 87 octane a few times and once had a problem in that the ethanol freed up some gunk in my fuel system and clogged the inlet to one carb. Ruined my day of fishing

As long as ethanol free 91 octane gas is convenient to get then I will continue to run it in my outboards.

Cheers~!