"dennis@home" wrote in message
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"The Natural Philosopher" wrote in message
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Probly needs a decoke and a shade of ignition advance..that keeps the
valves cooler. Set the gap correctly, and then loosen the distrubutoir
and rotate while idling until it start to slow down, then set it as far
advanced as possible without slowing..a shade of over-rich also helps
keep the valves cool.

Running rich helps the petrochemical smog too.
They all need scraping or at least banning from urban areas along with
other heavy polluters (not CO2) like buses.

Most buses can be hybrids, which is an ideal setup for their usage with
brake regen, etc. In the 1950s the Germans used flywheels in some buses to
clawback kinetic energy. Or buses can be just electric, which some are.

Yep, older engines pollute like crazy. The secret is eliminating the piston
internal combustion engine. It can only ever be dogs ear, no matter what
they do to it.