On Sun, 30 Jan 2005 05:25:15 GMT, "James Sweet"
wrote:


I change the oil in my home mower before each use, or every two
cuttings at the most. On US made single cylinder simple air cooled
engines the oil is the lifeblood and dirty oil will greatly shorten
engine life.


Now that's a little ridiculous, change the oil after every use? That's like
those people who change the oil in their car every 1000 miles. I've dealt
with enough 25-30 year old air cooled engines that were still in good
mechanical condition after obviously many hundreds of hours of use,
generally they had the oil changed occasionally but certainly not after
every use. Once a season is perfectly adaquate unless you're running 8 hours
a day, I change mine every year when I put it away for the winter.

I just checked in an old (1970's I guess) B&S service manual I have and they
specify oil changes ever 25 hours of operation so I probably end up changing
mine a little more often than that, but as you say oil does get combustion
byproducts in it, same reason a car driven all the time on the highway can
go a lot more miles between changes than one driven around town.

As for the lifetime ratings, the number of hours the warranty guarantees an
engine will last, and the number of hours it's expected to or actually will
last are two drastically different things, I would be absolutely shocked if
even the cheapest most shoddy lawnmower engine out there wore out sooner
than a couple hundred hours even if the oil was never changed (as is often
the case).

Not ridiculous to change it that often at all. As I did say most of
the engines I service go all day long and they get fresh oil at the
start of every day.
You'r also not considering that this is 30 wt non-detergent which
suffers viscoscity breakdown after just a couple of hours.
If you look at alot of those Briggs motors you'll noticed they're
mounted with the head to the REAR on the mower. This is absolutetly
the worst orientation for allowing air flow over the hottest part of
the engine. This only speeds up the process of breaking down the oil.

Yes in normal situations I'd agree about warranty vs. actual engine
life but I've had nothing but bad experiences with Briggs for the past
few years.
I've seen many burn up right out of the box, after running them for
just a few minutes.(AND yes we did put oil in them, every B&S
replacement engine come with a small bottle of Their own certified
oil.)
This is nothing more than shabby workmanship, plain and simple.
(All the ones I've gotten have been manufactured in the orient. A real
crime considering they tend to cost more than the other brands.)