Oil???

[bertsmobile1]

That is not quite correct. Compared to liquid-cooled automobile engines, small engines run hotter, operate under constant load, generate more oil-damaging contaminants, suffer from neglected maintenance, and are exposed to dirt, rain, and other extremes. Simply put, they are tougher on oil than most people think. Automobile oils are designed with fuel economy in mind, not durability.

All true sort of but that does not change the fact that zinc is not needed for mower engines because the scuffing forces are just not there
I can compress a B & S valve spring a small amount between my finger & thumb
I can not do that on my BSA engine , and it has 2 valve springs per valve and when new used plain oil with no zinc
The zinc thing is another case where the advertisers use the tiny bit of knowledge that most have about oil to confuse the issue to convince you to buy a product that you do not need .
IT is the Alaskan Elephant Repellant approach .
The most important thing with mower oils is the corrosion inhibitors because the engines sit around for so long
Next most important is the detergents to prevent the contaminants forming a sludge paste in the sump while it is sitting doing nothing .
Zinc was not important in any engines other than diesels till the 90's when start up emissions became law and oils had to be made way too thin so there was almost no viscous drag on the engine allowing the very first piston to do a full cycle to fire .

Mower engines are very very very very very very very low tech and very lightly strained .
The fact that they use cast con rods running directly on the big end journal should be enough for most .
But if you want some more convincing then look at the torque : cc ratio of a mower engine compared to an equivalent HP or capacity air cooled motorcycle engine.
That will show just how lazy these engines are

As for subject to misuse & abuse , yes 100% on the money there .
And this is the biggest reason why I try to get my customers to use plain mower oil & not the very expensive synthetic oil so they will change it every season on the final mow of the season .
I play with vintage motorcycles & when synthetics came out there was a rash of engine failures with bikes where the owners had switched to synthetics
Now there is nothing wrong with the oil as such but the oil holes, galleries and wells are designed for older higher viscosity oils so things like cams never got enough oil ( fixed by going up an index or two ) but the main problem was leaving it in there for way too long because the recommended oil change intervals on the bottle were 4 times longer than the engine was designed for .

 

[bertsmobile1]

The single most important thing about oil for mowers is the frequency of changing
The rest is of marginal importance
I am yet to check but perhaps mower engines designed for synthetics are made to tighter tollerances but I doubt it because higher precision cost a lot more on an exponential curve and mower engines are all made to a price which is why almost none of them use rolling element bearings and run directly on the crankcase casting .
A mower oil will be better than a air cooled motorcycle oil which would be better than a water cooled car oil .
But none of them are any good if left in there for too long
Cheap oil changes every season without fail will be better for your engine than very expensive oil left in there for 5 seasons .
If you have several vehicles that use the same grade of oil then run that if it makes your life simplier .
If you also blow snow then it is worth while changing the oil twice a year between seasons & running a much lighter snow grade oil in winter .

 

[deriter]

I guess I am failing on at least one item and that is changing the oil at the end of the season. It does make sense to take out the dirty oil and put in fresh oil to store over the winter. I do believe it is very important to change the oil out with the seasons. I will keep that in mind this fall. And the only reason I use multigrade oil is for easier starting in the fall when the temps drop.
Now for one more question, manual says 10w-30. Does my mower know the difference between 10w-30 and 15w-40? I mean is there a difference that I should be considering. Getting ready to change the oil out, new air filter, and maybe a spark plug. I am also going to install an hour meter just to see how much time is put on the mower.
Feel like I have be caged up all winter and anxious to get out and mow the lawn. lol

 

[bertsmobile1]

the 15 will be a tiny bit harder to pull start
There is really only 2 reasons for multigrade oils being developed
1) using a cheaper lighter grade of oil and / or second or third splits so more saleable product per barrel of oil
2) easier starting due to lower amount of viscious friction when cranking .
Some time around 1990 start up emissions became regulated
If you think back, your old car would crank for 30 second or so while it built up sufficient speed to start
Your 2020 car starts the instant you touch the starter & spins at full cranking speed strait away.
Low viscosity oils make this possible
There are other reasons but these were the drivers because the auto industry does nothing till new regulations force a change
Otherwise it is just bigger engines every year .

While oils are slippery, they all have drag and the higher the viscosity number the greater the amount of drag
SO more engine power is gobbled up to defeat this drag so it is not available to cut grass .

 

[MParr]

I have serviced small engines for 55 years. NEVER found an engine damaged from any of the recommended oils in this conversations as long as the level was proper. An oil class I attended informed me that the US regulations allow anyone to call it synthetic even if it is not and the only way to know if it really is synthetic is by the price. It is like the food that can be called what it is not. So much for the Government doing the right thing for the people. As engineering on cars has moved forward, they do have specific desires but even some of that is not for engine life, it is for milage. This level of design has not reached small engines with the exceptions of 2 cycle, hand held 4 cycle, and EFI engines and propane powered or natural gas where there are some legitimate requirements.

For me personally, I don’t buy a dedicated small engine oil. Living in the south, a minimum of 10W40 for my V-Twin. I like 15W40 HDEO and that’s what I buy. For single cylinder four strokes, a SAE 30 HD is all that’s needed. The important thing is keeping it topped up and the oil and filter changed at the recommended intervals. And, don’t forget maintaining the air filter as required.

 

[AtRo Racing]

My neighbor and I were talking about lawn mowers. We both have Toro Recyclers and I said I was going to have to tune up and change oil. I said I was going to put in 10-30 synthetic oil. He said you should use Toro's oil because it has added zinc for better wear on engine components. I was wondering what you folks think. Is this right or hype? And is 10-30 ok or should I use straight 30My mm

 

[AtRo Racing]

My neighbor and I were talking about lawn mowers. We both have Toro Recyclers and I said I was going to have to tune up and change oil. I said I was going to put in 10-30 synthetic oil. He said you should use Toro's oil because it has added zinc for better wear on engine components. I was wondering what you folks think. Is this right or hype? And is 10-30 ok or should I use straight 30 sae?

My shop has repaired over a 1000 lawnmowers, Tractors, and miscellaneous Outdoor Power Equipment a year for the last 50 years. We use nothing but SHELL ROTELLA T-4 15W-40 OIL in all 4- Cycle engimes without any failures. Robbie

 

[Bellcrank]

Thoughts to ponder about motor oil

“Without promotion, something terrible happens... nothing!”
-- P. T. Barnum

 

[Rivets]

AtRo in my part of the country 15W-40 is way to high viscosity for our cold weather.

 

[deriter]

Well, not to beat a dead horse, but my thinking on the synthetic oil was that I heard that synthetic takes the heat better and that it holds up better than regular oil. So I was thinking to get longer life out of the mower, then use synthetic. I see maybe I have been over thinking this?
Thank you all for you comments and info.