ESCAP 16mm gearmotor bracket

Mounting bracket for "ESCAP 16 Coreless DC 12V 540RPM Gear Motor With encoder 16MM" from ebay. Motor mounts to bracket with 2x M2 screws 5mm long. This motor keeps turning down to 0.1 Vdc, and each of the 2 (quadrature) encoder outputs delivers 3456 pulses per revolution of output shaft. Since the even pulses are consistently 17% different in length from the odd pulses, the encoder is probably the combination of two separate quadrature detectors, not quite 45 degrees apart. OpenSCAD file provided for bracket.