Generator fuel

Submitted: Friday, Apr 01, 2016 at 13:35
ThreadID: 131995 Views:5576 Replies:7 FollowUps:3
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What is the better fuel for a yamaha is2000 generator?
I have been told that running premium fuel causes the thing to run hot.

What do others use?

Thanks in advance
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Reply By: garrycol - Friday, Apr 01, 2016 at 13:47

Friday, Apr 01, 2016 at 13:47
If in doubt read the instructions - the fuel to use will be listed in the handbook.
AnswerID: 598068

Reply By: Ron N - Friday, Apr 01, 2016 at 15:30

Friday, Apr 01, 2016 at 15:30
Geoff - Page 11 of the manual says the generator engine is "designed to use unleaded gasoline with a RON of 91" - i.e., regular unleaded petrol.

There's no benefit whatsoever in using premium fuel in a little generator such as yours - and the information that you got, that they run hot on premium fuel is very likely to be correct.

Air-cooled engines run pretty hot at the best of times, and they don't have a huge margin for temperature increase before the oil starts to break down and it then fails to lubricate properly. Engine seizure is then on the cards.

Yamaha EF2000is Manual

Cheers, Ron.
AnswerID: 598073

Reply By: Bushranger1 - Friday, Apr 01, 2016 at 17:07

Friday, Apr 01, 2016 at 17:07
Hi Geoff,
Standard fuel is just fine.
Ensure you use fresh fuel that has not been sitting around for months as it loses it's volatility & gums up the carb. Many engine problems are attributed to this.

If I am not going to run my small engines for a while I add fuel stabiliser (Stabil brand) to the fuel.
This keeps the fuel from going off but will not fix fuel that is already past its use by date.
AnswerID: 598078

Reply By: mountainman - Friday, Apr 01, 2016 at 18:16

Friday, Apr 01, 2016 at 18:16
I always use premium on small motors.
Motor bike, lawn mower and sniper.
never had a issue of letting the fuel go a bit old and happy to use it with nil bad effect.
uses soo little the higher grade fuel is worth the cost as it runs cleaner and fuel doesnt go stale soo quick or for a long long time.

running premium and getting engine to run hot is rubbish.
For starters your using a better quality fuel.
burns cleaner, more power.
bit like saying use the typical motor oil in the sump and then run to a semi synthetic oil with no ill effects. .
ooh but that will cause engine to run hot
only if you use a lower grade
its a better quality product
AnswerID: 598082

Follow Up By: garrycol - Friday, Apr 01, 2016 at 20:22

Friday, Apr 01, 2016 at 20:22
The quality of the fuel irrespective of number is the same - the higher the number the higher the octane rating which has nothing to do with the power of the fuel (calorific value) but its ability to resist pre ignition so extra power from an engine using higher octane fuel comes from running a higher compression ratio ad ignition settings not from the fuel itself.

So 98 is not is not a better quality fuel than 91 it is just a different fuel for a different purpose.
FollowupID: 867203

Follow Up By: Member - Scott M (NSW) - Saturday, Apr 02, 2016 at 13:37

Saturday, Apr 02, 2016 at 13:37
spot on Garry. This is the great myth about higher octane fuel. The higher octane is there to prevent high compression motors suffering pre-ignition. Actually the lower octane is more flammable. Higher octane isn't necessarily better quality fuel. It just contains more additives to retard ignition.

Any knowledgable mechanic I've spoken to always say use the manufacuters recommended minimum, as you get no benefit (except higher cost) for using a higher octane.
FollowupID: 867227

Reply By: bakers - Friday, Apr 01, 2016 at 18:31

Friday, Apr 01, 2016 at 18:31
Hi Geoff

Standard unleaded (91 ron) is fine but would never use E10 in any small engine that is expected to sit around.
As stated above stabil can be used to prolong the life of the fuel for up to 12 months

AnswerID: 598084

Reply By: Ron N - Saturday, Apr 02, 2016 at 13:03

Saturday, Apr 02, 2016 at 13:03
The science of fuel combustion still confounds a lot of people and there are many people who have a poor understanding of it.

Higher octane (premium) petrol is designed for high-compression engines.
Petrol BURNS in an engines combustion chamber - it doesn't explode.
If petrol explodes in a combustion chamber - this is called pre-ignition or detonation - and it produces the classic "pinging", or light knocking engine sound, as it does so.

A higher octane rating means the fuel has more resistance to detonation - PULP actually BURNS more SLOWLY, than the lower octane ULP.

The additional POWER from premium fuels comes not only from the slightly higher calorific (or higher joule) value of the premium fuel - it also comes from the higher COMPRESSION RATIO of the engine - that is DESIGNED and OPTIMISED, to run on PULP.

Virtually every car engine today is fitted with a knock sensor (to prevent engine damage) - whereby the ECU will automatically retard the spark timing, to reduce or eliminate knocking or pinging.

To take full advantage of the benefits of PULP, the ignition needs to be advanced - or the ECU needs to be reprogrammed (reflashed) to tune the fuel mixture and ignition parameters to suit PULP.

When you use PULP in a small stationary engine that is designed to run on ULP - there's no ECU fitted, and there's no manual spark adjustment - so therefore there's no ability to advance the spark timing to take advantage of the higher octane rating of PULP.

Therefore, when using PULP in a small air-cooled engine, you have a fuel which is SLOWER BURNING - and this means that combustion temperature peak, from the combustion process, is now occurring in the exhaust port, rather than the combustion chamber.

As a result, you have a higher Exhaust Gas Temperature (EGT) - which leads to a burnt exhaust valve, if the high EGT continues for an extended period.

As anyone on here with aviation experience knows - on an aircraft piston engine, EGT is a crucial measurement that is a primary focus of the pilot.
EGT is one of the most critical engine parameters that needs to be watched carefully.

Engine manufacturers will often give a maximum EGT figure for their engines and this must not be exceeded to prevent engine damage.

EGT is also a crucial number to extract the best fuel economy or power from an engine - and EGT is monitored by pilots, via the mixture control lever, to enrich the mixture to make full power for takeoff, and to lean the mixture to increase fuel economy, once cruise level is reached.

Adding extra fuel into the air-fuel mixture is utilised to cool an engine by reducing combustion temperatures.
This is the reason why all the big old American petrol engines were thirsty.

The manufacturers designed them to run on a rich Air-Fuel Ratio (AFR) to prevent exhaust valves from melting at constant highway speeds, as most American engines/cars were run at.

In a small air-cooled engine, cooling is carried out by the oil - by the piston and conrod - and by the finning on the head and upper cylinder area.

When you use PULP in a small air-cooled engine - which is optimised by the manufacturer to use ULP - then the later combustion temperature peak is reducing the ability of the piston and conrod and oil to carry away the heat of combustion - and transferring the temperature peak, to the exhaust port and exhaust valve.

As a result, due to the inability of the small air-cooled engine to reset its spark timing (either manually or automatically) - or to raise its compression ratio - to take advantage of the higher octane rating of PULP - you're wasting your money, gaining no extra power - and risking a burnt exhaust valve, by using PULP in it.

Sorry about the long post - but fuel combustion in an engine is a complex process that always involves a lot of factors, all of which need to be understood to get a grasp of the full picture.

Cheers, Ron.
AnswerID: 598106

Reply By: Echucan Bob - Monday, Apr 04, 2016 at 15:53

Monday, Apr 04, 2016 at 15:53

Connect a solar panel to the DC outlet. Uses much less fuel and is quieter, but only runs during daylight hours.

AnswerID: 598187

Follow Up By: TerraFirma - Monday, Apr 04, 2016 at 21:16

Monday, Apr 04, 2016 at 21:16
FollowupID: 867341

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