GY6 150cc backfire issue

[parbs]

thank' for the feedback.
I check the fuel line, it drains with no issues.
I noticed at initial startup, the rpm is about 1200-1500, normal rev. After 10-15 minutes of running & when it runs very rough/backfire, the rpm at low idle registers 6000 rpm. Note, this is not the true rpm. It rev's at same idle as the initial cold start up. I'm beginning to think it is the coil pickup sensor/switch.
The tach runs of the coil pack/pickup. I don't think it could be the magno.