Shell V power/BP Ultimate

[Stubby]

Ok but which fuel has less ethanol in it?

 

Not many people know this ( I did not ) but apparently there is a code number somewhere on the pump that denotes the ethanol content . How you interpret the number I am not sure .

[TimberCutterDartmoor]

The MPG gauge tells me 31 mpg on cheap supermarket fuel and as much as 38 mpg on a good run on premium. Its a computer what reads mpg so I cant be sure on its accrual. I should at some point brim tank and measure miles.

 

I always use petrol from 'proper' petrol stations (not supermarkets) in my machines.

 

Not sure if it makes much difference but it's only a slight price increase!

 

Ages ago I started a thread on here about an engine oil (diesel) research project I was involved in and still am - the initial time period for the project has been stretched to 5 years (used to do research for the TRL so been in and out of the business for years). We've recently paused the testing to carry out integrative fuel testing since we needed to re-bench the fuel quality in the tests. The above two quotes are included as although we have a way to go before we decide the best derv for our purposes the mainstream vs supermarket theory is quite accurate; refinery source the same, 9/10 yes, additive package not at all similar. Thus far we have found staggering differences between best and worst case fuels in mixed duty consumption but remember multiple variables have to be ironed out including:

 

1) Barometric Pressure.

2) Relative Humidity.

3) Ambient Temp.

4) Point in service cycle (i.e. around UOA)

5) etc

6) etc

7) etc

[shavey]

Not many people know this ( I did not ) but apparently there is a code number somewhere on the pump that denotes the ethanol content . How you interpret the number I am not sure .

 

that is interesting it would be good to find out where this number is and compare all the different companies what ethanol percentages are

[Pete Mctree]

I have ruined 2 saws this year by accidentally putting supermarket fuel in them. The pots are scored & when I settled it out it contained an alarming amout of water/ethanol. As a result I spend my money wisely - not always high octane ,but anything but supermarket fuel. My saws cost thousands @ earn me that too so I try & look after the the best I can.

[TGB]

...

The use of 97 octane will actually reduce power in a lower compression motor as the detonation is delayed too much for peak performance...

This would be pinking would it not.

[GardenKit]

This would be pinking would it not.

No, this would be the exact opposite to 'pinking' which occurs when the detonation is too soon in the cycle. This occurs with fuels too low in octane for the compression of the engine.

Also with old fuel which has lost its octane rating.

 

But you will not hear pinking on a saw like you would in an old car.

[mowandgo]

I have concluded there is a vast differnce between fuels on the pumps. Shell/BP/Esso i think are quite good theres little difference between there premium fuels on garden machinery. However supermarket or cheaper fuels are very poor and for 5p a litre less is not worth the trouble. Why is ethonal so bad? How does it harm your engine?

[GardenKit]

Why is ethonal so bad? How does it harm your engine?

 

Ethanol is bad for many reasons.

Sure, its good for the environment because its made from a crop which absorbs CO2 and puts out O2, and the bi-products are all put to good use. Use 10% ethanol in fuel and the oil reserves last a bit longer.

 

But the bad points (not in any particular order)

 

It attacks very many soft metals and plastics, in effect slowly dissolving them

 

It absorbs moisture which bonds with the ethanol until its too heavy, then the water falls to the bottom of the tank and the ethanol follows it. The first fuel your engine then draws is Ethanol and water, causing it to run very hot,

but ethanol does not bond with most 2 stroke oils, so when your engine runs on the ethanol from the bottom of the tank (assuming there is not too much water present to run at all) there will be no lubrication for the engine and engine damage will quickly occur. The oil will be bonded with the petrol sitting above the ethanol.

 

The ethanol that has bonded with the water very quickly goes into 'phase separation' At this point the ethanol/water mix forms a gel in the tank and carb. The remaing fuel has a lowered octane rating and, if the machine is lucky enough to start it will destroy itself quickly

 

Ethanol contains 35% oxygen, way more than petrol so an ethanol rich mix runs lean requiring the fuel/air mix to be richened or a lean sieze can occur.

 

Petrol with 10% ethanol runs around 10% hotter than petrol, which can cause engine damage.

 

Ethanol vaporises easily causing more hot start issues due to vapor lock.

 

Ethanol encourages galvanic corrosion, so dissimilar metals corrode when in contact, e.g brass and aluminium in carbs.

 

Ethanol speeds up the decay of the petrol, and encourages the seperation of the oil from the petrol, so petrol over a month old really should not be used.

 

Many scored pistons are blamed on the operator not having mixed sufficient oil with his petrol, but are in reality due to phase seperated, stale fuel.

 

There are many more negatives, but I think this covers the main issues.

[Stubby]

Ethanol is bad for many reasons.

Sure, its good for the environment because its made from a crop which absorbs CO2 and puts out O2, and the bi-products are all put to good use. Use 10% ethanol in fuel and the oil reserves last a bit longer.

 

But the bad points (not in any particular order)

 

It attacks very many soft metals and plastics, in effect slowly dissolving them

 

It absorbs moisture which bonds with the ethanol until its too heavy, then the water falls to the bottom of the tank and the ethanol follows it. The first fuel your engine then draws is Ethanol and water, causing it to run very hot,

but ethanol does not bond with most 2 stroke oils, so when your engine runs on the ethanol from the bottom of the tank (assuming there is not too much water present to run at all) there will be no lubrication for the engine and engine damage will quickly occur. The oil will be bonded with the petrol sitting above the ethanol.

 

The ethanol that has bonded with the water very quickly goes into 'phase separation' At this point the ethanol/water mix forms a gel in the tank and carb. The remaing fuel has a lowered octane rating and, if the machine is lucky enough to start it will destroy itself quickly

 

Ethanol contains 35% oxygen, way more than petrol so an ethanol rich mix runs lean requiring the fuel/air mix to be richened or a lean sieze can occur.

 

Petrol with 10% ethanol runs around 10% hotter than petrol, which can cause engine damage.

 

Ethanol vaporises easily causing more hot start issues due to vapor lock.

 

Ethanol encourages galvanic corrosion, so dissimilar metals corrode when in contact, e.g brass and aluminium in carbs.

 

Ethanol speeds up the decay of the petrol, and encourages the seperation of the oil from the petrol, so petrol over a month old really should not be used.

 

Many scored pistons are blamed on the operator not having mixed sufficient oil with his petrol, but are in reality due to phase seperated, stale fuel.

 

There are many more negatives, but I think this covers the main issues.

 

Perfectly put Garden . Just like to add in the U.S. they are having an epidemic of small engine failures due to the higher ethanol content over there .

[leswold]

Just read this whole thread with interest. Would it be best to empty fuel tanks they'll not be used for a while, to stop ethanol/moisture content doing it's worst?