Matronics Email Lists :: View topic - Octane degrading with storage time

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Octane degrading with storage time

Matronics Email Lists Forum Index -> RotaxEngines-List

View previous topic :: View next topic

Author Message

JohnF

Joined: 13 May 2010
Posts: 124

Posted: Mon Dec 20, 2010 2:45 pm Post subject: Octane degrading with storage time

Are there any real octane enhansers readily  available? I get the impression that the ones generally advertised are pretty  much 'snake oil'

  

 Second question: what lowering of octane rating can  you expect in the real world? In other words, how long is 91-octane 'good' in a  912uls?

  

 Thanks for your views.

   [quote][b]

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Mon Dec 20, 2010 6:29 pm Post subject: Re: Octane degrading with storage time

Hi John,



I wouldn't keep fuel longer that 4 weeks. That's what Rotax recommends. No matter what type of container you store fuel in it will evaporate and or have octane degradation and loose other additives. Don't store any more than you will use in that time and don't fill your plane up if you plan on letting it set for months. If you plan on not flying for a couple of months just drain the fuel at a low point bleed. Octane booster won't work for us and unless you feel like throwing the dice with $10-$12k in rebuild cost then just use fresh fuel. It will drop down to to 87-88 octane before you know it. If that happens either drain and put fresh 91 oct. in or add at least 50% of 100LL.

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

JohnF

Joined: 13 May 2010
Posts: 124

Posted: Mon Dec 20, 2010 6:59 pm Post subject: Octane degrading with storage time

Thanks, Roger. I was not looking to increase octane in the mogas (91) but 

wondered about 'rejuvenating' 91 that has been in the plane longer than I 

would be comfortable with...says something over 3 weeks. If the weather 

would cooperate I could keep the gas fresh by simply flying a lot, which is 

what I want to do, but winds have been so darn bad of late that flying 

wasn't worth the beating you'd take doing it. I  will note your 

recomendations and follow them. Thank you.



John

---

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

m.tucciarone(at)hotmail.c
Guest

Posted: Tue Dec 21, 2010 4:26 am Post subject: Octane degrading with storage time

?I have been flying a 912S for about 7 years now. I have had gas in the 

plane for longer than 4 weeks. As soon as I buy gas, I add Stabil to it even 

if I plan to fly that day. I have never had a problem. I have never seen any 

varnishing in my float bowls. My engine has never even hiccupped.  I learned 

this at a Rotax seminar taught by Phill Lockwood.



--

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Tue Dec 21, 2010 5:21 am Post subject: Re: Octane degrading with storage time

I've heard this "octane degrades over time" story a lot over the years. Several years ago I researched this and found (and lost) a petroleum engineer's explanation of how gasoline goes bad over time. He explained all of this in layman's terms and debunked the "octane degrades" part, i.e. octane does not degrade. However, gasoline does go bad for other reasons. I wish I could find this but have failed to do so, so far but will keep looking. 



However, I did find the following which I believe to be a reliable authoritative source (but can't guarantee that) which does not even mention octane but does describe how gasoline does go bad over time. 



http://www.straightdope.com/columns/read/2668/why-does-gasoline-go-stale-so-quickly



As this source recommends, I  have been adding Sta-bil to my stored gasoline beginning in the late fall when my flying frequency falls off dramatically. It works well in my experience.

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Wed Dec 22, 2010 6:04 am Post subject: Octane degrading with storage time

John,

  I too always add Sta-bil to my fuel and it does help. .In the past I sometimes had run-on at engine shutdown with my 912 when I had "vintage' fuel in my tanks. It acted like an old car with bad gas. As an experiment I added Lucas brand octane booster to the fuel and it stopped that from happening.I have actually done this on a few occasions and for that reason I will say octane booster does work. Some brands contain alcohol so if you were decide to try it be selective as to the brand.

  Best option of course is to have fresh gas but if I can't fly for awhile ,I would use the booster . There is an unknown here and that is octane booster chenicals and its effect on  fiberglas tanks(in my case)

                                           Dick Maddux

                                           912UL

                                            Milton,Fl

 [quote][b]

- The Matronics RotaxEngines-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List

Display posts from previous:

	Matronics Email Lists Forum Index -> RotaxEngines-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum