HLAviation wrote:
Ya know, a 2 stroke doesn't have to oil the bottom end through the fuel.
I've always wondered why the OB manufacturers didn't change the design to a
closed crankcase design with a dry sump oil system and a simple
supercharger. Cheaper, simpler, proven.

They have Aviation, the Ficht & Optic just pump tiny amounts of raw oil
into the crankcase, because there is no fuel going through it just air.

This is one of their problems, the small amount of oil just sits there
(that's why they claim not to use much oil) getting hotter & hotter
until it bakes behind the lean mixture induced overly hot rings.

The Optis use a piston pump (true it's almost the same as a truck's
brake pump) to pressurise a second inlet manifold which has the
injectors, then they shoot air & fuel into the chamber via another big
problematic injector(inlet valve), with it's plumbing drives lubrication
etc etc it's more complex than even the latest 4 strokes.

K


"Calif Bill" wrote in message
k.net...

"Harry Krause" wrote in message
...

JamesgangNC wrote:

Not taking a position on Karen's usefulness but I have to agree with

her

position on 2 strokes. There is just far too much established 4

stroke

engineering that can be used to make reliable riskfree 4 stroke

products.

Trying to make a 2 stroke low emission is just not worth it. Doing so
negates one of the biggests advantages of a two stroke, it's

simplicity.

Do you have some legitimate statistics that demonstrate that four stroke
outboards are measurably more reliable and riskfree than two-stroke
outboards. I mean generally, say, for the last 50 years of production,
in horsepowers of 150 or more. Big, highly stressed engine. The real

deals.

I'll be glad to read them with great interest.

Not opinions. Genuine, scientifically based statistics.


--
A vote for Nader is a vote for Bush;
A vote for Bush is a vote for Apocalypse.

50 years is too far back. Those 2 strokes were simple. The Optimax and
Ficht of the last 10 years have not shown a lot of reliability. Witness

the

demise of original OMC. With the big Honda a basic high performance car
engine with a dry sump. there should be great reliability. The E-Tec,

etc,

with the addition of air compressors, low amount of lubrication at the

lower

end as the requirements for less oil and emissions. Makes for a engine

that

is on the edge of reliability.
Bill