Hi - I have an issue with my 1330 engine I am trying to sort, and could use some help. I have a fresh 1330 with a hif44 carb, sw5 cam, big valve 12g940 head, 1.3 roller rockers set to 15 thou. Engine wants to idle at 1600 -1700 rpm, and won't come down anywhere near 1000. Here's what I've checked so far (in addition to hunting and searching the forum and web for clues...): idle screw is out (not touching throttle cam), choke is off (cable is slack), no signs of air leak from carb to intake area, intake to head area, crankcase breather (connected to carb), dizzy vac (either end), spindle ends, choke area. Mixture is close (plugs are chocolately and lifting piston raises rpm slightly then settles at orig speed (although high)). Damper cap is LZX 1511. Dashpot oil is sae30, spring is red. Needle is BCE. Timing is close (10 deg at 1700, vac off). Coil is new, elec dizzy.
Here's what I'm not sure of that might be contributing: butterfly has poppet valve with spring that seemed soft, piston has about 1/8" vertical free play prior to damper being engaged - not sure if that is normal. butterfly valve has some side to side play when opened. Car has slight run on, but if I back off the mixture, the run on lessens. It's getting too much air from somewhere...but where? I am missing something...but what?