Still now some problem remains

Flight test today revealed that Hornet with YS 45 FR motor has still some problem of overflowing of fuel at the carburetor throat caused by one way valve failure, some small dust prevent the pressure in the fuel tank stop. And the pressure activates diaphragm valve resulting this inconvenient phenomena, overflow. As a quick countermeasure,  I arranged an another one way valve in series into the fuel line, if some dust might  keep opening one of them, a residual one would play a part of pressure shut out action.
A black colored rubber like dust relatively big one was observed in the fuel silicon pipe of PILOT Ace B with OS 32 F motor, the main needle angular position suitable for peak point changed as a matter of fact.
I have been suffered from clogging dust in the fuel line, I have never been experienced like this!  Of course, fuel filter are positioned everywhere according to the requirement. However hard I might pay attention to the point, some dust exists in the fuel line, how come?. Nozzle tip of fuel supply pump, fuel tank weight, near by fuel supply nipple on the carburetor, no specific change was not done this time.
PILOT Fighter lacks fundamental motor power to draw F3A maneuver patterns, so it was changed ENYA 15 to ENYA 20 already, the crank cases are almost the same between them and their weights also.
Let's try them tomorrow, and see what will happen?.