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FUEL MIXTURE - 1988 JOHNSON 6
Me wrote in news:Me-
:
How do you install Roller Bearings on connecting rods? All the
Roller Bearings used in engines I have ever seen, were on
single cyl engine cranks that could be pressed on from each end.
I would think that any split shell Roller Bearing, would be less
robust than a regular shell bearing in the same application.
Me just wondering........
Outboards use a single-piece forged crank with split bearings out of
necessity. Jetskis, however, use whole bearings and split the crank up
into several pieces that are pressed together then pinned to hold them in
place. My 1997 3-cyl, 150hp Yamaha GP1200 twisted its crankshaft 22
degrees, which of course screws the timing all up something awful, as it
sheared the pins holding the crank together. Single piece forged cranks
are just fine with needle bearings wrapped around more solid parts....
These bearings in a 2-stroke are only there because there is no oil
available for lubricating cheaper sleeve bearings like in your car. That
would require oil pressure to keep the parts from grinding together, of
course. Outboard manufacturers don't spend a single dime more than they
absolutely must to make it to the end of the warranty period, I can assure
you. No valve train, no big alternator (a bunch of coils inside the
flywheel with magnets spinning around them like they were in the 1930's
isn't expensive, no matter what the man told you about the stator costing
$400!) I think they got rid of the points and went to a CD because
electronics is cheaper than points and machining cams.
A 2-stroke outboard is very simple, indeed.....just like a 2-stroke diesel
moving that 950' containership down the channel out in the harbor.....
--
Larry
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