"bob zee" <cam509@linuxmail.org> wrote in
news:bi81lm$679b0$1@ID-177997.news.uni-berlin.de:

>
>
>
> "E. Meyer" <e.meyer@ieee.org> wrote in message
> news:BB6C4C80.D56B%e.meyer@ieee.org...
>
>> >
>> Blowing out the carbon ceased to be necessary when they switched to
> unleaded
>> fuel. That being said, I still do it whenever I get the chance, just
> 'cause
>> its fun.
>>
> not to pick on *you* directly, mainly i needed to put my opinion out
> there for the world to see. :~)>
>
> there has NEVER been a reason to blow out the carbon on any engine.
> if it is tuned right, it will never have any carbon to deal with!
> this is true from the ancient in-the-block-valve technology of my
> lawnmower right up to the I-VTEC technology of my honda. carbon is an
> symptom of a problem elsewhere. mixture too rich, engine never up to
> operating temperature, etc.
>
> oh yeah, since i brought up the briggs & stratton engine, ever notice
> the spark plug on your mower just loaded with carbon? yes, they set
> them things up at the factory to be extremely rich. how do you blow
> the carbon out of it? :~)>
> they are set rich so that they run cooler (ever notice your mower
> seems to cut better when it is cold outside?) a lean briggs on a 95
> degree (F) day will melt in no time!
>
> my wife would never buy the 'blow the carbon out' trick...


bob,
While I agree with your statement about the current crop of computer
contolled fuel mixture engines on cars, Briggs and Stratton engines
do have carbon buildup problems on most of their engines because most are
flathead designs, not ohv. (Honda stopped importing flatheads into the
US about 1984 except for one very small engine.)
Flatheads have carbon buildup because of excessively large quench areas
and crevice volumes,
something an ohv angine was designed to minimise, even before emissions
reductions were one of the major design targets of new engines.
As to the carbon buildup in your Briggs and Stratton engine, and also
for all flathead engines, there is generally a recommendation in your owner's
manual to periodically remove the heads and scrape out carbon deposits or remove
with chemicals run through the engine as it is operating . Onan has such chemicals
in spray cans, and having done this once and seeing and smelling what came out
of the engine, I will never do that again!
Large flathead engines especially in generators will not produce full power
if not decarboned every 250-400 hours depending on load and type of oil used.
If the engine in your car does not get up to full operating temp and at
that time is not loaded to about 85% or more of the full power it can
develop, it would help to get it into that target zone to help keep it clean
just dont wait too long and do it suddenly or you can fuse the loose deposits
onto the plug insulators, glazing them. A better method is to take your car
onto a little travelled highway and gradually increase speed to bring
up combustion chamber temperatures slowly.
Unless your car is almost never driven on the highway at all, this is not necessary .
Most people drive on the freeway enough to do this anyway.