hi i just rebuily my carby and put it all together but when i press the speed then let got it dosnt fully go up it gets stuck until you move the throttle up!

also on low revs why is their like a hesitation laggy feeling and when you fully press brakes and floor the speed the engine dosnt gain speed it just stays at one low speed?

also i advanced the timing 2 degrees so from 7 to 5 would this cause any harm i use 98 octane fule?

Thanks!