I think "out of kilter" comes from the Irish language word "ceirtle", meaning a ball of yarn, thread, string, or cord. When the thread or yarn comes "as an gceirtle", and gets tangled up, the weaving comes to a halt. The phrase in quotation marks would be "off the ball".
"As ceirtle" would not apply to any particular ball, but would be a more generalized expression. The diminutive "ceirtlin"(acute accent over the last "i" to denote that the vowel is long) is used in expressions such as "ceirtlin tochraiste" to mean a very hardy, strongly built, active man--a tightly-wound ball as it were. Primitive technological terms applied generally to all technology.