This is a question for the experts amongst our readers.
Now that I finished my second 143 I'm once again puzzled by the fresh-air-intake setup of this model.
I already noticed this particular setup with my 143 2 years ago but didn't worry much about it.
Here is what's puzzling me:
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Left you see the 143. In its hood there is a open window between carb housing and cylinder-area (upper green tip)
and the single intake opening above the choke lever ist still closed as cast by factory.
On the right side there's a 133 super which doesn't have a connecting window between cylinder and carb housing but
rather has two fresh-air intake at the rear end of the hood (blue tips).
IMHO this means the 143 always intakes pre-warmed air as opposed to the 133 s (and 123 which is set up in similar manner)
which always gets fed with cool air.
Since the 143 has more power and more displacement one would think the 143 might be a little more thermal critical than its lower
powered siblings, but the reverse seems to be the case.
What might be the reason for this unexpected intake setup?