Fuel Additives

[corvette33]

I recently purchased a CTSW. I am sure this has been discussed before so I am sorry if this is redundant. At the Light Sport Expo in Sebring I asked several Light Sport manufactures and a Rotax representative about the used of Stabil with fuels containing ethanol. The answers seemed very vague. I have a 4 stoke Yamaha Outboard and my dealer strongly advocates the use of the Stabil product or similar products by CRC. In reading forums in the Light Sport industry it seems ethanol is a factor as it is in the marine industry. What are some recomendations? In the winter time the plane will possibly not be flown for a week or two at a time. I know this presents some problems so I do have interest in the additive issue. I understand I can use 100LL for times that I may fly infrequently but I am curious about the use of additives similar to Stabil on a continious basis.

Thank You.

[Roger Lee]

Hi Corvette33,

 

Glad to see you made it over to our forum. Most of these guys will introduce themselves and give you great advise. There are a lot of senior CT people here and techs to help out.

 

As far as the Stabil, it will not hurt your plane, engine or tank. You can leave the fuel set for a month and not have any issues. So for two weeks don't bother with any additives and I wouldn't worry for a month either. If it were going to set a long time like a couple of months or more you could add a little 100LL to help fuel stability. Does Stabil really help?, maybe for the long term i.e. months, but probably won't do much for you short term like 4-6 weeks. Ethanol will not be an issue for you in the CT even in a humid climate. The fuel can adsorb a lot of water, but the good thing is it will burn it right through the system and you'll never know. I wouldn't worry about a lot of water adsorbing because of humidity it just isn't an issue usually. The time to worry is if you saw water actually come out of the gascolator. That means the fuel is fully saturated and needs to be dumped. 100LL won't absorb water and water falls out into low spots easily and that's why you are more likely to see water with 100LL. You could pour a quart of water in each full wing tank with ethanol and would never see it. The marine industry sits in water so we are not quite as susceptible to the quantity of water in the fuel as they are.

 

I hope this helps some.

 

 

p.s.

How about a name so we don't have to call you Corvette33.

[corvette33]

Hi Corvette33,

 

Glad to see you made it over to our forum. Most of these guys will introduce themselves and give you great advise. There are a lot of senior CT people here and techs to help out.

 

As far as the Stabil, it will not hurt your plane, engine or tank. You can leave the fuel set for a month and not have any issues. So for two weeks don't bother with any additives and I wouldn't worry for a month either. If it were going to set a long time like a couple of months or more you could add a little 100LL to help fuel stability. Does Stabil really help?, maybe for the long term i.e. months, but probably won't do much for you short term like 4-6 weeks. Ethanol will not be an issue for you in the CT even in a humid climate. The fuel can adsorb a lot of water, but the good thing is it will burn it right through the system and you'll never know. I wouldn't worry about a lot of water adsorbing because of humidity it just isn't an issue usually. The time to worry is if you saw water actually come out of the gascolator. That means the fuel is fully saturated and needs to be dumped. 100LL won't absorb water and water falls out into low spots easily and that's why you are more likely to see water with 100LL. You could pour a quart of water in each full wing tank with ethanol and would never see it. The marine industry sits in water so we are not quite as susceptible to the quantity of water in the fuel as they are.

 

I hope this helps some.

 

 

p.s.

How about a name so we don't have to call you Corvette33.

[corvette33]

Thank you very much for the infomation. I suppose I am more concerned with the ethanol situation than I need to be. My dealer is adding some accessories to our CT. We will pick it up when we return from our Florida home in April. We traded a Piper Arrow on a CT. At this point I have only flown a CT for a demo flight for about 45 min. so we are looking forward to spring and getting started with the Light Sport experience. I look forwaed to gaining many needed "tips" from this web site. Thank you again.

[Runtoeat]

Hi Corvette33. Believe that you have asked a unique question since I don't recall someone wondering about Stabil? I live in Michigan which is similar climate to yours in PA. For your CT, no worries using Mogas if you do two things. 1. Buy from "high volume", clean gas stations that sell national name brand fuel. 2. Drain or use up the Mogas in your tanks and fill with 100LL if your CT is going to sit for more than 3 months. I used to use Stabil in my fuel for outboards and classic cars. Still had concerns with fuel. My method now is to completely drain all fuel tanks in the fall, run the fuel completely out of the carbs, and use fresh fuel in the spring. Do not store the empty fuel tanks on the boats but store these in a protected area. No more troubles.

 

If you haven't done so yet, crab a cup of coffee and go thru this "Engine/Rotax" section of the forum. If you've been on other forums, you may find this forum to be one you'll hang out more often due to the friendly atmosphere here. No matter what aircraft one may be interested in all are welcome.

[chanik]

Even in the worse case that you did have phase separation, the Ethanol adds only 3-4 octane points to MOGAS so you could assume you had 87 Octane after pulling out all the 'vodka' You could bring that back up over 91 with even a 30% mix of 100LL. Octane is roughly additive so it's basic algebra to figure it out. Ethanol is 116octane. Take 90% petroleum fuel at 88Octane and 10% alcohol at 116 and you get 91Octane. Stabil works to inhibit gum formation which could drop 2-3points off octane so it seems like a good idea if you're going to sit out several months. But in winter you won't get gum anyway as it really comes from warm fuel exposed to air. Sitting for months in a Tuscon summer is the dicey scenario.

[corvette33]

Thanks guys for all your advice. I don't see the aircraft sitting for more than a month at the most without being flown. It appears this won't be a real problem with the the fuel issue. Hopefully it will be flown more often but sometimes weather becomes a problem. We do keep the aircraft in a hanger but it is unheated.