Yamaha EF2400IS Generator Engine Oil?

G'day Greg
The 10 W means it is 10 viscosity when the oil is cold and the 40 means, that cold 10W grade doesn't thin down to more than 40 would thin to when hot.
Note: the 40 aspect will be far thinner when hot than 10W is cold.Therefore the engine is hot running on thin oil as they all do.

I have a Honda 2 and it specifies 30W but I run it on 10W40 Mobil 1.
Mobil 1 seems to seal the rings better on most engines and therefore less usage of sump contents. Sealing also means the oil stays cleaner for longer.

PS, although probably a bit unnecessary, I run my Honda 4stroke whipper snipper and Honda Motor mower on the same stuff. Rarely have to change oil because it is dirty.

All the stuff in the bike shops will be synthetic or semi synthetic and designed to perform in a motor that is under a lot more stress in a wider range of environments, temperatures, rpm ranges and lean angles than a generator that just sits there, nice and level chugging away at a governed RPM.

I'd just go into an auto parts store and buy some mid priced 10W40 for petrol vehicles or stationary engines from a reputable manufacturer and use that.

As a bonus it will be less than 1/2 the price of the Yamalube so you can change it twice as often and still be ahead.

I use 10W40 diesel engine oil in my ride-on, generator and pressure washer and for years in the bike (push mower gets monograde). It works fine, meets the specification for petrol motors but has more detergents in it to keep carbon in suspension.

Greg & Julie - The Yamalube 10W-40 is a semi-synthetic oil formulated to meet the JASO MA oil standard.

The MA, MA1, MA2 and MB oil standards are set by the Japanese Automotive Standards Organization, so that oils can be produced with improved specifications for motorcycles - and the MA1 and MA2 oils are produced particularly for those machines with wet clutches, that have the clutch oil supply combined with the engine oil.

The MA is a lower-spec oil that is not designed or approved for use with wet clutches - but it is basically a straight engine oil designed for high-RPM air-cooled engines.

The MB standard is a lower spec again, for use in motorcycles where the clutch and gearbox use separate oil compartments from the engine.

Air-cooled engines operate at increased temperatures to water-cooled engines, and the oil in these engines has the task of assisting in cooling, as well as lubricating.

Naturally, it has to have additives that make the oil perform well at higher temperatures, than those encountered in water-cooled engines.

All you need for your Yamaha EF2400iS is any brand of oil that meets the JASO MA oil standard.

Penrite's 10W-40 is a recommended alternative to Yamalube 10W-40.
In the link below is an explanation of the JASO MA and MB standards.

If you click on the blue link ("Click here"), it leads to Penrites oil selection webpage, where you can select your model to find the correct Penrite oil.

Penrite Technical Bulletin

On the oil selection page, your menu selection needs to be ... > Power Saws, Brushcutters and Trimmers > Yamaha [Generators] > EF2400iS

Many other brands of oil will also meet the JASO MA oil standard, you just need to go to the oil manufacturers webpage and find their selection chart.

Yamaha have a store locator page - but you will find the Yamaha generator retail points usually only sell Yamaha generators as a sideline to their main business.

Yamaha generator store locator

The days of bricks-and-mortar shops dealing in only generators and pumps and small engines - and fixing same - are long gone.

Even my local mower shop has moved 3 times in the last 5 years, and downgraded his operations to a smaller setup each time.

Cheers, Ron.

Hi Greg & Judy,

Another vote for Mobil 1. Yes it is synthetic, but will not do your generator any harm, in fact as has already been stated, will actually improve the performance and reliability of your engine. The only downside is that it is pricey.

I ran Mobil 1 in my 1998 Petrol Landcruiser exclusively, and it had well over 300,000 kms on it and was still going strong when I traded up.

I also used Mobil 1 V Twin in my Harleys over the years. Again, this is a synthetic oil, but has been specifically designed for air cooled motors such as motorcycles & stationary air cooled petrol engines. In fact, Harley Davidson approached ExxonMobil to supply their Mobil 1 V Twin in Harley Davidson branded containers. ExxonMobil refused as the Mobil 1 V Twin is a proprietary blend.

Macca.

Go to any lawn mower shop SAE 30 will be sufficent not like a generator has to work in temp ranges like a automotive engine does.

Think the auto chains will also have it in a small 1 l container they use bugger all oil.

One thing to do is never fill it and leave fuel standing in tank this will go satle causing startign issues later on, and add a fuel additive (stabiliser) this will help assist slow down the degradation of the rubbers in the carburettor.

can of aerostart or start ya bastard is useful to have esp if you have dodgy shoulders like I have and pulling stregth isn;t very much

Hi all,

Many thanks for your comments and suggestions; they’ve all been very informative and helpful.

Cheers

Greg

Greg & Julie.
Since you possibly don't know what servicing has been done on the generator, it is a good idea to run it on Mobil Delvac 10W40, it is a diesel engine oil and will cause no harm to the engine, but it will clean the inside of the engine of buildup, if there, and leave the innards clean when drained. Many petrol engine oils don't clean very well.
A couple of hours running with it will do the cleaning and then use a 10W40 of your choice, or better if you prefer.