My YS 91 has air bubbles in the fuel line that goes from the pump to the carb. They appear at idle but disappear as I increase the throttle. Is this a problem? I'm new to YS motors. I'm also having a little trouble with a reliable idle, sometimes it's fine, sometimes it slows and dies. Low speed idle screw may not be set just right. I bought the motor barely used, good compression. I'm not using fuel dots, instead I'm using 2 easy fuelers.

Thank you for the help,
Lonnie