Hi all,
I have been trying to sort out this problem for a few days now. I have a PZ27 carb on a 150cc FT162FMJ engine.
When I open the throttle completely my engine revs upto around 8000 rpm, if I hold it open it slowly drops to 7000 rpm and starts to "hunt/miss".
While riding on occasion I get a small backfire and I get the hunting/missing.
I have opened the the carb and checked for any dirt and found nothing.
I have adjusted the main needle on the top of the carb up and down and tried to set the carb with the adjusting screw with each change in needle position.

I set the idle up to 3000 rpm and adjust the screw - what I have found is that I have to screw it all the way in before there is any change to the rpm and I have to unscrew it almost all the way out as well before there is any change to the rpm.... I am not getting any rpm change while slowly screwing it in or out.

I am going to check valve lash this evening.
Am I correct in thinking the engine should rev up to 10 000 plus...or do they only rev to 8000 rpm?

Any help or direction will be greatly appreciated.

Thank you all in advance