john smith wrote:

Is this the difference beween having a low compression, low horsepower,
no-mixture control engine and having a high compression, high
horsepower, mixture controlled engine?

Sooty plugs indicate either a too-rich mixture or oil burning. I would say it's
the result of having no mixture control in this case.

George Patterson
A diplomat is a person who can tell you to go to hell in such a way that
you look forward to the trip.