Husqvarna recommends not to use high octane petrol

[pidgeon1]

Husqvarna recommends not to use high octane petrol, I take this means super 99 .

Can anybody give me the answer ?

I filled my 10lt can when filling my car should I use this ???

My Machines Honda Mower, Brigs & Stratton mowers. Flymo petrol mower.

two stroke Mix Stihl hedge cutter and jonsered hedge cutter


Thanks.

 

[Burnerman]

The higher the octane, the higher the compression ratio used to be the golden rule.....certainly I cant see it doing any harm and I use whatever I have in at the time.
There is a train of thought (based on nothing whatsoever as far as I know) that the higher octane fuels don’t like to mix with two stroke oils so well and that some of the metallic elements added to the same may cause spark plug whiskering that plagued us in the past.
On any two stroke engine (or 4mix) a quality lube is crucial.
John

 

[lostinthelight]

I believe some premium grade fuels contain little or no ethanol so that can't be a bad thing

 

[pidgeon1]

I believe some premium grade fuels contain little or no ethanol so that can't be a bad thing

I try to use Tesco Momentum 99 in my car so fill mower can same time. :

From Tesco site:
Tesco: "We sell two grades of unleaded: regular 95 octane Tesco Unleaded & super unleaded Tesco Momentum99. Both contain up to 5% bio-ethanol, derived from various sources including sugar cane."

 

[Burnerman]

I’ve always assumed that’s why the nozzles are marked E5 (ethanol 5%) and B7 (biodiesel 7%)?
John

 

[xm77]

My local tesco is now selling standard unleaded as E10 grade (10% ethanol)

 

[Captain Nemesis]

The higher the octane, the higher the compression ratio used to be the golden rule.....certainly I cant see it doing any harm and I use whatever I have in at the time.
There is a train of thought (based on nothing whatsoever as far as I know) that the higher octane fuels don’t like to mix with two stroke oils so well and that some of the metallic elements added to the same may cause spark plug whiskering that plagued us in the past.
On any two stroke engine (or 4mix) a quality lube is crucial.
John

Ive never used 2-stroke oil in a mower, just regular engine oil, sometimes synthetic.

 

[Captain Nemesis]

I filled my 10lt can when filling my car should I use this ???

Does your car actually need high-octane petrol?

 

[xm77]

I recall recently on another forum possibly an aviation one, someone doing the calculations properly by testing it on their car accurately.
The result was that yes the miles per litre did improve using the higher octane petrol however the penalty of the extra price for the super-unleaded meant that it was not worth it in terms of the overall result of £ per mile

 

[pidgeon1]

Does your car actually need high-octane petrol?

YES.

 

[pidgeon1]

I recall recently on another forum possibly an aviation one, someone doing the calculations properly by testing it on their car accurately.
The result was that yes the miles per litre did improve using the higher octane petrol however the penalty of the extra price for the super-unleaded meant that it was not worth it in terms of the overall result of £ per mile

My Tesco selling Momentum99 137:9

 

[JohnD]

YES.

that's very strange. Is it a very old car?

what is it?

 

[pidgeon1]

that's very strange. Is it a very old car?

what is it?

Foreign Red and Very Fast.

 

[JohnD]

oh, an old Fiat fire engine, with no engine management system?

 

[Captain Nemesis]

I recall recently on another forum possibly an aviation one, someone doing the calculations properly by testing it on their car accurately.
The result was that yes the miles per litre did improve using the higher octane petrol however the penalty of the extra price for the super-unleaded meant that it was not worth it in terms of the overall result of £ per mile

Which is why I asked pidgeon if his car needed it. Some do. His does.

But a lot of people buy the stuff thinking its better, when with modern cars, even high performance ones, it really isnt.