Non ethanol fuel question

Skippydiesel

Well-Known Member
Joined
Nov 29, 2020
Threads
10
Messages
173
The burn rate difference between 87 and 92 is negligible in stock small engines. We are not doing max HP pulls on a dyno.

Has anyone seen a small engine damaged from preignition?
No High octane fuels, will not cause "knocking" in small engines.
They will have little if any effect, good or bad however your expenditure will increase for no benefit.
 

Skippydiesel

Well-Known Member
Joined
Nov 29, 2020
Threads
10
Messages
173
The issue isn't preignition; it's incomplete or partial combustion. High octane fuels are designed to combust at a much higher compression than small engines produce, on average around double.
In small engines there is no significant difference between the burn/ power developed, of a high or low octane fuel (subject to the low octane fuel not being below that recommended by the engine maker).
It would take sophisticated engine testing equipment, well outside most home/small business owners access, to see any difference at all.
Using fuel of an octane rating above that advised by the engine maker, will do no harm to the engine but will certainly lighten your pocket unnecessarily.
My comments are limited to petrol engines - diesel being a whole other subject.
 

Tiger Small Engine

Lawn Addict
Joined
Dec 7, 2022
Threads
2
Messages
1,130
In small engines there is no significant difference between the burn/ power developed, of a high or low octane fuel (subject to the low octane fuel not being below that recommended by the engine maker).
It would take sophisticated engine testing equipment, well outside most home/small business owners access, to see any difference at all.
Using fuel of an octane rating above that advised by the engine maker, will do no harm to the engine but will certainly lighten your pocket unnecessarily.
My comments are limited to petrol engines - diesel being a whole other subject.
A local competitor small engine shop apparently puts VP fuel in equipment (that needs it) that he works on. Customer gave him a 3 star rating in review because he was charged $50 for about a half gallon of gas. Shop owner reply is that he uses this fuel so he can “guarantee” the repair/service. I guess the “warranty” runs out after a half gallon of high speed gas.

I am always putting fuel in customer equipment that are low or out. Amazingly it is 87 octane 10% ethanol gas, and have no problems or comebacks as a result.

Compression in a healthy 4-stroke engine should be 120 psi plus when tested. Common sense should tell people that 2-6 points of difference in octane rating for a small engine is negligible at best. We are talking about a relatively low compression engine (compared to vehicles) that runs at 3600 rpm. Not a NASCAR or top fuel dragster where it actually matters.
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
59
Messages
15,345
I’m smarter than you. My theory’s are facts, your theory’s are just what you want to believe. Remember, everything you read on the World Wide Web is the absolute truth and based on time honored facts, so what ever you say won’t change my mind.
 

stevestd

Active Member
Joined
Aug 31, 2016
Threads
1
Messages
52
The new Sheetz gas station near our house happens to sell ethanol free fuel, however the octane rating seems to be 90 (instead of the usual 87)
Is this higher octane safe for my Kohler VTwinand for my Honda self propelled mower?
 

Gord Baker

Well-Known Member
Joined
Aug 21, 2018
Threads
1
Messages
395
The new Sheetz gas station near our house happens to sell ethanol free fuel, however the octane rating seems to be 90 (instead of the usual 87)
Is this higher octane safe for my Kohler VTwinand for my Honda self propelled mower?
Higher Octane Fuel simply burns slower so there is no knock on High (9.7 t0 12:1) Compression engines.
You are lucky to be able to buy Ethanol free fuel. Can't in Canada thanks to Lieberals.
 

Rickcin

Well-Known Member
Joined
Jul 4, 2012
Threads
73
Messages
279
Higher Octane Fuel simply burns slower so there is no knock on High (9.7 t0 12:1) Compression engines.
You are lucky to be able to buy Ethanol free fuel. Can't in Canada thanks to Lieberals.
That is really pathetic, those people are ignorant ❗
 
Top