How can i fix my ec12 hitachi electric air compressor

This problem is caused by either the starter capacitor or the in-tank check valve. Ez to check. With no air in tank, start compressor; if motor hums or has difficulty suspect capacitor. If motor starts, partially fill tank and unplug the power. Check for air leaking at the pressure switch or air coming out of the air inlet (remove the air filter). If air leaking, replace check valve. If no air leaking, again let out all the from the tank and connect power. Allow the compressor to fill and shut-off. After the compressor fills, again listen for air leaking from the pressure switch unloader valve. If air continues to leak from unloader, replace the check valve. Good luck

If other people have problems with AIr leaking and have metal parts in the Check valve look for metal parts in the pressure hose IF your Check valve has problems it can be have metal pieces from out the menbrane or comming from one or some metal reducing adapters.