[MichaelP]

Why when 91UL is available are we putting 100LL in aeroplanes designed to use unleaded 71 or 80 octane in their engines?

Mechanic told them to use 100LL.
Leaned out to clear mag drop, "point taken" I was told.

Please support 91UL, it's better for us who operate unleaded old engines that suffer stuck valves and fouled plugs through having to use the wrong fuel, 100LL. We need 91UL to be available in the future.

[Lockhaven]

I remember seeing a list published on the forum that was from the FAA saying which dinosaur engines could use UL91, does anyone have it to post here again.

[Gas Guzzler]

UL91 is always my fuel of choice, however it's not available universally and when it is it's often more expensive. with the current high prices many will want to make the saving by using 100LL

[Paul_Sengupta]

Please keep using 100LL as it'll ensure it's still available - my engine can't run on UL91!

[aerofurb]

Lycoming publish (and regularly update) Service Instruction 1070 which lists specified fuels by engine model:

https://www.lycoming.com/sites/default/ ... 0Fuels.pdf

[Lockhaven]

aerofurb wrote:
> Lycoming publish (and regularly update) Service Instruction 1070 which
> lists specified fuels by engine model:
>
>
> https://www.lycoming.com/sites/default/ ... 0Fuels.pdf

That's the one I have seen before thanks, its been updated since I last saw it because now they are saying my dinosaur engine can use UL91 and automotive fuels although I have heard the engine maybe ok to use it but some fuels affect the hoses.

[Skybluepink]

Is there a list of airfields carrying UL91 anywhere please?

[Dominie]

Skybluepink wrote:
> Is there a list of airfields carrying UL91 anywhere please?

Off hand, I can name only Halfpenny Green as having UL91 - I'm sure there are more but I don't always draw fuel on landaways.

[Ibra]

If the engine has STC or is on the approved list (airframe has CS-STAN where you make your own sticker) then I would not touch anything that mechanic work on with a barge pole, let alone fly it !

[malcolmfrost]

Popham carries UL91 and 100LL and they are both the same price usually. £2.10 last time I looked.
If you use Skydemon, go to "Find a Destination" and select Fuel Availability and it will show airields with both types and the last price noted by users.

[Rob P]

Lockhaven wrote:
> because now they are saying my dinosaur engine can use UL91 and automotive fuels
> although I have heard the engine maybe ok to use it but some fuels affect the hoses.

AIUI the hose issue is motor fuels with ethanol, not UL91 off airfields

Rob P

[Dman]

For microlights, East Durham has UL91
£2 lt

[aerofurb]

Regarding the use of 'automotive' fuels, SI 1070 includes the following:

'EN 228:2014:

Automotive fuels - Unleaded petrol - Requirements and test methods Ordering Requirements:

Vapor Pressure: Class A

Oxygenate Content: For blends containing one or more oxygenates, oxygenate content are not to exceed 1.0 volume percent.'

As Rob P said, UL91 should not be an issue as it is basically unleaded Avgas. The problems lie with automotive fuel that contains Ethanol and/or other additives that may cause issues with fuel tanks, sealants, hoses, seals, valves and filters etc etc.

[VRB_20kt]

Shobdon has UL91

[josher]

Compton has 91 so does Henstridge.