After many trials i finnally got the new carburetor (the one with the big venturi) perfectly tune up in flight, excellent power , excellent flight , and good engine performance, after landing I refuel for another flight, but this time the engine turns richer and richer as it flies, all by itself (I did not change anything), until it finally quits .

I think this was too big carb for the engine and consequently unreliable. So I go back to fix the original one , the wt-500.

I don´t know much about the pop off pressure, but the problems came at less than mid-range (3000-4000 rpm), so according to Flypaper 2 ,I should make the spring shorter in order to retard this pop off effect
How about canceling forever this pop off effect ?