I'm running a low time Quadra 35 with the Tillotson carb, still a bit rich, on a Zinger 18 x 8 at 7300 RM. Can peak it to 7500 if I want. Initial start settings for the needle valves are: Low Speed= 1 1/4 turns open, High Speed=1 turn open. Adjusting the low speed needle too lean for a good idle can mess up the high end. Run at full throttle at the initial settings and set the high end. Then adjust the idle for a good transition, making sure its not too lean (it will heat up and quit if it is). Then reset the high speed needle. Points and plug should be set at 0.015". The B&B Carb Adjustment Tool is handy to have as it allows adjustments from behind the prop with the engine running (see picture).