Hi all, thank you very much for the feedback really appreciating.
Rspears you got perfectly the problem of the language barrier ... english plus technical ...
in the meantime i found an extract of the service manual (attached). If i'm correct for the CH350 the original degrees should be 28°-31° with 10° BTDC.
so if my understanding it's correct i should use the RED limiter at 16° and this should be safe correct ?
if you see different just please let me know and i'll communicate to the harbor people.
Here the problem is that there are not machanics knowing this engines ... today they are only box checking ... they plug the test and the box is telling them what to do.
you can't imagine how long was taking me to restore those 2 engines (will post a couple of pictures).. all parts from USA (inclusing the 2 blocks) and a lot of study by myself.
thanks in advance, ciao.

ServiceManualGasEnginesPrior1980-spec.pdf