I have Hummel 94/86 (45) horse motor. I am having issues with getting my Mikuni 28mm carbs tuned and the engine smoothed out. I am running a fuel pump and Holley Regulator. (Gas tank is behind the seat). The regulator is set as low pressure as it will go, hopefully around 1lb. I'm also running 170 main jets in both carbs. My floats are set at 17mm, the top end for 28mm carbs. I was still getting overflow when the floats were reset so I changed out the main needle valve to a 1.5 and went down to a O-6 Needle Jet. So, I'm not getting overflow now but, when I start to throttle up there's a hesitation and/or stumble (actually it seems to have always done this) I also have the needles set to the 2nd notch from the top. Once I'm past it, it smooths out and seems okay in runup. And last but not least, the number cyl. 1 spark plug looks rich and the number 2 cyl. spark plug looks lean. Can anyone provide me some assistance on what to do next? Thanks, Bill
