a little off topic,but since its a 4st question, I have a used OS 91fs surpass a older one I have been having trouble finding a good idle with the mixture, I reset the mixture screw acording to the instructions, but can't seem to get a good idle out of it, any tricks out there I am missing,like clean the carb or something basic it seams to be running rich and gets good high end RPM's 10,200 but wants to stall at the low end it does smoke a bit but runs good just doesn't want to idle for me.should I check the valves I hate to run in circles for something simple I may be over looking.