Hi, I can see little bubbles in the line between pump and carb on my 91ST as well, it is not an issue. My motor runs a tad rich right across the range and is and should be cool enough for you to touch it for at least 15sec's (on the crank back-plate). Lots of smoke and even gurgles a little every now and then. It is important that you replace the glow plug after every 5litres (1 Gallon?) of fuel. I have also found that good quality fuel makes a huge difference, I run it on Xfuel 15% and have no hassles (alt=5500ft). Good luck!