Trying to setup gasser and a Saito low end using a tach.
Have used three different brand hobby tachs(hobbico, Hanger 9, Globe). Can not get consistent good readings outside in sun light to properly set up my low end needle. Have plane facing sun or direction of sunlight shooting thru prop from back within 4 to 6 inches. Readings are way off or not consistent. Calibrated fine, batteries good. Can not set up my low end with out consistent readings. What am I doing wrong?
HELP