Given this last post, would think maybe the carb is having issues--Pin Head has a rebuild video that it is spot on--get a rebuild kit from SMP(Standrdard Motor products){best quality and most accessory parts) {check your carb build No.} there is no included keeper clip for the power valve-but still avail from Toyota--~$3)--take you a couple of days to complete the rebuild(but who cares) you will learn your carb and know it;s function--follow the steps--not that hard at all--
I'm assuming you have the original Aisan Carb)
I'm assuming you have the original Aisan Carb)