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Wilbur Hubbard Wilbur Hubbard is offline
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First recorded activity by BoatBanter: Feb 2007
Posts: 2,869
Default mixing gas and oil questions

"Wayne.B" wrote in message
...
On Tue, 26 Oct 2010 16:54:44 -0400, "Flying Pig"
wrote:

Never mind whether or not a certified mechanic can be trusted or whether
or
not I selectively read. At least one poster has verified doubling the oil
during breakin so it stands to reason that it MIGHT be possible that the
manual actually says the same about severe operating conditions...


I don't think so. That's when you're likely to experience
pre-ignition/detonation due to the lowered self ignition temperature
of the fuel mix.




Duh! Increasing the oil to fuel ratio does not lower the self-ignition
temperature. It raises it. We are not talking diesel engines here. We are
talking two-stroke gasoline engines with their relatively low compression
ratios.

Try running a two-stroke (two-cycle) engine on pure two-stroke oil and they
won't self ignite to combustion EVER! Even a spark plug won't make the thing
fire.

Try running them on half and half gas and oil and they might just barely run
given a source of ignition like a spark plug before it fouls with oil in
about a minute but they won't self-ignite EVER.

Try running them on nothing but gasoline and they will have a much higher
likelihood of self-ignition (aka detonation, knock or ping) for about a
minute before the piston seizes to the cylinder wall.

I hate like hell to say it but SKIPPY IS CORRECT. Increasing the oil to fuel
ratio will not damage the engine from detonation, etc.


Wilbur Hubbard