I have a YS 91 AC has about 3 gallons ran through it. the problem i'm having is the motor will run with the high speed needle valve closed tight. it runs perfect at this setting if I open it up an 1/8 turn it runs rich and if I leave the regulator flush it still runs rich with the high speed needle valve closed I have to tighten up the regulator turn the regulator to about 1/2 to 1/3 way in before it will run well even with the needle valve closed I have checked the valves the intake valve was way out of whack and when we set it I notest that now that I am at the end of the threads on the intake side we took out both rods and they are the same length also replaced the diapfram and plunger and every thing else in there

any one know what is causing this problem