When the throttle is "closed" it is still pulling fuel/oil, if it didn't the
engine wouldn't run. Outboards have far more HP than a Saab 2 stroke ever
had and they don't need to keep spinning to lub things up.
"Dave Hinz" wrote in message
...
On Tue, 1 Mar 2005 19:31:16 -0000, Haaken Hveem
wrote:
Is it possible to lubricate a supercharger with oil premixed in the
gasoline?
On two strokes oil are pre-mixed in the fuel, to lubricate the engine.
The oil-fuel mixture usually passes from the carb and in to the
cranc-case,
and then to the cylinder.
I dont like the idea of having to mount a external oil pump and plumbing
to
lubricate the supercharger.

Well, the first thing that comes to mind, is how will the supercharger
get lubrication when the throttle is closed? Saab's 2-stroke cars
(1940's through late 1960's) overcame this by putting a "freewheel"
in the drive train - a one-way slip clutch that let the engine go back
to idle when you took your foot off the gas, so it's coast freely.
The supercharger is driven by the crank rotation, yes? So, you'd
have to either put a freewheel (one-way slip clutch) in, (hard at high
horsepower), or come up with some other way to lubricate it.

Emissions would be another concern, as well as oil flow into the parts of
the supercharger where you need it. Better, I think, to inject oil to
where the supercharger needs it - if it goes into the induction system
from there, that's OK, but it eliminates the overrun problem and the
problem of hoping the oil gets to where it's needed.

Dave Hinz