On Thu, 18 Jun 2009 09:40:56 -0500, Michael Dobony
For 4 stroke engines do NOT use standard automotive engine oil as it
has no zinc compounds in it any more for extreme
pressure/anti-friction. It has been taken out for emission control
reasons - if the engine burns any oil with the zinc compounds in it,
the catalist is compromized. Apparently it is still allowed in the
heavier oils like 20W50, but that doesnt mean the brand you use will
The special 4 stroke equipment and bike oils still have it. Use them
for best engine life.
BS...a small 4-cycle engine has higher lubrication demands than an
automotive engine? I don't think so and B&S doesn't either...
"Briggs & Stratton lawnmower oil is formulated...and approved by Briggs
& Stratton engineers-Warranty certified and recommended in all Briggs &
Stratton manuals-A high quality detergent oil classified SJ/CD by the API"
The API classification is nothing different than that for most modern
I seriously doubt you'll find any ordinary small 4-cycle engine have any
special requirements more stringent than the above.
Remember, higher API ratings do NOT translate to better lubrication.
They just meen a newer standard.SM oil is significantly inferior to SJ
for heavy duty applications, old engines, and "L" Head air cooled
engines. Don't know if any of the current crop of OHV small engines
has roller cams but I doubt it.
Air-cooled engines always have hotspots, no matter how well-designed.
That's why even Porsche and VW eventually gave up on air-cooled engines.
Briggs is not going to spec anything other than regular oil.
It would be a marketing nightmare for them, and a warranty issue.
"Don't buy a mower with a B&S engine. You have to use B&S oil, and that
stuff is expensive." They know that the original owner is rarely going
to put enough hours on the engine to wear it out, and even then it won't
be blamed on anything in particular. How many people are going to run a
mower 10 years until it just won't run anymore, then realize "If only I
had used motorcyle oil I'd get another 5 years out of it." ?
As to wear additives, it's true that the best of them has been
eliminated for the sake of emissions, specifically catalytic convertors.
That's a great tip on using bike oils. I'm going to check with my Lucas
rep and see if their Motorcycle Synthetics will work in my non-catalyst
cars. I think racing oils should also still have the anti-wear zinc and
Yabbut the thread was for small lawnmower engines, not racing or other
extreme duty applications. There's little need nor anything to be
gained from using anything greatly exceeding the OEM's API
recommendations in normal use.
Virtually any quality automotive oil of proper viscosity rating of the
last 20-30 years will be more than adequate since the advent of the
higher-temperature running auto engines beginning in the 80s for the
emission controls. In the 50s thru say 70s the requirements were pretty
minimal and some might show some temperature breakdown in air-cooled
engines I'll agree but that's pretty much gone by the by...
Again, high performance bike engines, etc., etc., aren't/weren't the
subject. Using such won't hurt anything and the small quantities
required means it won't really cost a whole lot extra but it generally
isn't really going to make any difference ever be able to tell.
As noted upthread, we're running some 30-40 yr-old small engine
equipment regularly. For most of their lifetimes (until Farmland Co-op
closed their refinery and quit manufacturing it) they ran on an
all-purpose API SE/SF/SD multi-grade that included full engine warranty
(including the turbochargers) service and a drained oil sample test kit
returned at every change for all of the trucks and tractors. After that
went away and w/ the arrival of the larger crankcase capacity tractors
went to bulk JD multi-grade but not synthetic -- JD did not recommend
switching to synthetics on engines formerly not on them. Use it in
You have not QUITE understood what I'm saying. The 20 and 30 year old
oil is PERFECT for lawn mowers etc. The levels of ZDDP (google it if
you don't know what I'm talking about) were very high back in the
'70s. Today's automotive engine oils have virtually NONE. ZDDP
protects sliding parts. Camshafts and camfollowers. Connecting rods on
splash lubricated engines. Ditto for main bearings. There is NO
pressurized layer of oil between the moving parts in a B&S, Kohler, or
Techumseh l-head engine. The ZDDP prevents metal-metal sliding
friction from welding the parts together.
You can more than double the life of the average small 4 stroke engine
by using the correct oil over using current off-the-shelf automotive
oils. If you put a lot of hours on a fleet of small engines (snow
removal/lawn service or generator/construction air compressor use) the
inconvenience/expense of finding the right oil will save you BIG
You ARE using the right oil in the small engines. JD Multi-Fleet and
SD rated oils ARE right for these engines. SM rated oil is NOT.
For anyone to recommend otherwise they obviously do not know API oil
ratings and/or small engine lub requirements.
But the intended point is (which my other response didn't do well) that
they _could_ have spec'ed a more stringent API classification but
didn't. It's not that there's any shortage of grades from which to
choose to meet the needs of the engines they're designing.
That they didn't indicates something... :)
My points were two:
Air-cooled engines can have localized hotspots that exceed the temps
found in automotive watercooled engines. Speaking only of areas touched
by the oil.
Current API specs have all but eliminated the traditional, and most
effective wear reducing additives so as not to foul your cat convertor.
To get the wear inhibitors back, you have to look at oils made for
engines without catalysts - race cars, motorcycles.
Will small engines last a long time using motor oils formulated tot he
current API spec?
"Can", yes. Smaller and less performance driven engines less likely.
I'd also wager quite a bit that the engine manufacturers look at
temperature distributions quite a bit in the design process.
That doesn't mean that there aren't different than the traditional wear
additives currently in those oils. There are some very smart folks
doing lubrication design these days w/ far more sophisticated chemical
modeling tools, etc., than in those days of yore.
OTOH, is some other selected ad hoc oil any better? Not necessarily.
The primary disagreement I have is the conclusion drawn that OEMs simply
more or less randomly select something in making those recommendations
and that there is something somehow wrong w/ newer oils simply because
they don't necessarily use the older formulations.
Again, specialty applications are something different than the ordinary
There are a lot of very intelligent mechanical engineers convincing
the automotive manufacturers to go to the more complex and expensive
roller tappet camshafts to make engines last running the de-contented
engine oils mandated by the emission control requirements.
But usually. They will be providing oils with lots of ZDDP in them.
GENERALLY the small engine manufactur supplied oil is roughly
equivalent to multi-fleet or racing oil.
Are you a mechanic? In particular a small engine mechanic? Or a
mechanical or lubrication engineer? I'm not an engineer, but I AM a
mechanic (among other things) and have worked on a lot of small and
air-cooled engines in the last 45 years.
I am now thinking this is what happened to my weed eater. My daughter
to her friend without asking me. I think they ran regular gas
through it and it
has never worked right since and I have had it in the
shop more than it has run
Air cooled engines DO have higher lubrication requirements - and the
low TBO or lifespan of most small engines definitely affirms that.
About 98% of the older small engines will last a WHOLE LOT longer with
oils containing ZDDP. Any engine with flat tappets will have
significantly less cam wear with ZDDP. The only reason current auto
oil does not have it is because it can affect catalytic converter
life. Any SL or previous engine oil is acceptable for small engine
use.. Racing oil and Deisel or Multi-Fleet oil is also acceptable.They
all have about 12ppm ZDDP, compared to a maximum of 0.08%
Today's roller tapet engines are much less demanding lubrication-wise
than flat-tappet engines.
From B&S FAQ--
All 4 stroke cycle spark ignited engines
Fuel must meet these requirements:
* Clean, fresh, unleaded gasoline.
* A minimum of 87 octane/ 87 AKI (91 RON). ...
* Gasoline with up to 10% ethanol (gasohol) or up to 15% MTBE
(methyl tertiary butyl ether), is acceptable.
Except as noted earlier for older engines since ethanol is widespread
and in some areas mandated, it would be most surprising if the engine
manufacturers weren't building their engines to run on the available
fuels. (They aren't variable-fuel systems, though, so E85 is out since
they require new carburation, etc..)
While B&S does recommend adding fuel stabilizer to ensure fuel doesn't
get stale since most homeowners don't use fuel very rapidly, I'm
convinced that's an avoidance policy to attempt to minimize customer
complaints rather than a real need. If a little additive can all of a
sudden make fuel perfectly fine for 24 months, it would be quite
remarkable the fuel itself as manufactured isn't able to last even 10%
of that time span.
I've routinely let equipment over-winter w/o any special treatment and
never in 40+ years had any issues the following year/spring/summer.
I just took an old B&S on a tiller that hadn't been touched for 10 years
and the gas left in that tank was not as some might have one believe,
gel nor were there any significant deposits, etc. Dump the contents of
the tank and rinse it out, put a little carb cleaner through the jets, a
new plug and little thin oil in the cylinder and spin it a few times to
lube it up a little. After that it started on about the third or fourth
pull and runs just fine, thank you very much... :)
The lore is far overblown from the realities in my estimation and
according to my experience.
For current products. Many of us run products that are a decade or more
There is also a difference between "run on" and operate reliably over
I've been storing fairly large quantities of gasoline for 1yr+ for years
and I can definitely tell you that Sta-Bil makes a huge difference. I
can also tell you that since we started getting alcoholic fuel it's
storage ability without Sta-Bil has decreased dramatically over the
non-alcoholic fuel without Sta-Bil. I don't yet have a solid
determination if Sta-Bil can keep the alcoholic fuel good as long as it
can the non-alcoholic fuel.
In 25+ years I've had a number of items with issues in the spring after
being stored over winters and in every case it was stored with untreated
Probably had Sta-Bil or similar added then, since I've seen equipment
left a mere two years with nasty sour fuel in the tank.
Not in my estimation nor experience.
PS: An ultrasonic cleaner full of warm Simple Green works wonders for
reviving a carb that's gunked up.
And again, w/ the possible exception of seals or some plastics, it's
fine. The only problems would be with much older equipment that was
designed for leaded fuel which hasn't been available for almost 20 years.
I'm still running a JD 112 that is at least 40, a JD S92 that is at
least 30 so don't suspect you've got anything on me wrt the age of the
I see no point in storing "large quantities" of any fuel for over a
year. I was speaking of simply over-wintering, etc., typically 6-8
months max and not large quantities. What's the point in that, anyway?
Sorry, I've had 15 years more and don't have problems--what can I tell
you other than I don't store fuel longer than a year.
I can definitely assert it did _NOT_ have anything at all done to it
other than load it on the truck when we moved it and unload it and put
it in the shed here when we arrived.
All I can say is it has never been an issue I've ever seen over the
If I ever see one, I'll give it a go... :)
Doubt it would have helped on the lead-salt deposits in the old mower I
mentioned elsewhere in the thread, however...
I have a 30+ Deere 110 riding mower, a Kubota B7100DT tractor, etc.
The point is to have fuel on hand to refuel the mower for the 3.5 hrs or
so it takes to mow the lawn, have fuel to keep the generator going
during power failures, and also reserve fuel for long trips.
This fuel was generally well under a year as well, with the equipment
having been last fueled and run ~Oct and restarted in Mar or so.
Prior to your acquiring it.
Someone gave me a pressure washer they couldn't start. I pulled the carb
off, gave it 10 min in the ultrasonic cleaner, blew it dry with
compressed air, reinstalled it and the engine started right up and has
run fine ever since.
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