High test or regular fuel?

[Benday]

What is the recommendation regarding fuel quality? Cheaper fuels have ethanol which breaks down and/or absorbs water so I have been told. Is there a long term accumulation problem with varnish in the carb jets and needle valves? Any additives designed to overcome this problem?<br />Thanks<br />Ben

 

[Jack Shellac]

Re: High test or regular fuel?

Use the octane fuel recommended by the manufacturer and always buy name brand gasoline and you should be OK. You are correct that alcohol is not desirable. It will attack some kinds of fuel hose and internal parts of your motor. Although you will get differing opinions on this, I always run 6 gals of gas with Gumout in the spring. My big motor [Johnson] is 12 years old and has never had any carb or fuel related problems. I also store with stabilized gas in carbs and run it every couple of weeks in the winter.

 

[ob1jeeper]

Re: High test or regular fuel?

LOTS of fuels (cheap or not) have ethanol added to help "clean our environment"... Ethanol enhanced indolene fuels DO burn a shade cleaner, thus the governmental push for all of us to use them.<br /><br />MTBE (Methyl Tercerary Butyl Ether) is the other most commonly used additive, you will see listed on the pump, especially in the Southwest, and in So Cal.<br /><br />Since Ethanol is a member of the alcohol family, it does have a slight affinity for absorbtion of moisture (not as badly as methanol...the stuff the indy cars & sprinters use...), but it can absorb moisture also.<br /><br />If you live in a "colder" climate, you will find available at many stores, "fuel de-icer"... It's basically denatured or "wood" alcohol, which is used to emulsify the water in fuel, so it can't freeze into large enough chunks to cause problems.<br /><br />Anyway... I'd suggest you minimize longer term storage issues, by adding a fuel stabilizer (there are a ton of brands on the market, ALL with the same basic ingredients, so any will do...) then topping off the tank(s) with the normally recommended fuel for your engine.<br /><br />This way the air-gap at the top of the tank is minimized, which will allow the minimal amount of atmospheric air (which can be laden with a bunch of moisture during fall/winter/spring, thus minimizing the amounts of moisture the fuel can absorb... PLUS, with the stabilizer in the fuel, it will reduce the tendency for the fuel to form varnishes, or "gum" deposits.<br /><br />The next time you then use it, if it's been more than 8-10 months, I'd drain off approx. 1/2 tank, then top off with fresh fuel, and go boating. the drained off fuel can be re-added in small increments, trying to mix it with fresh fuel 1/2 to 1/2, until it's used up.<br /><br />If it's been less than that 8-10 month period, just get it out, and use it normally. AND anytime you plan on letting the boat sit for more than a week or two, you'll want to park it with a full tank of fuel, to mitigate the build up of deposits, and the propensity for the fuel to absorb moistureout of the air...<br /><br />Hi-test VS Regular is your devcision. As long as you are using the minimum octane recommended by your manufacturer, you're "OK"...<br /><br />Hope this helps...<br /><br />GOOD LUCK Obiwan Jeeper

 

[JB]

Re: High test or regular fuel?

Octane rating has nothing to do with "quality" of gasoline. It merely refers to the fuel's ability to retard preignition.<br /><br />87 octane (or better), alcohol free, unleaded gas is recommended by most manufacturers.<br /><br />As Jack says, use what your manufacturer recommends.

 

[rickdb1boat]

Re: High test or regular fuel?

Hi Ben<br />Which Motor are you talking about? I see in your previous questions that you have several. Best to run 87 when in doubt, unless pinging occurs. High octane can be more damaging in the long run if your motor is not designed for it.