Just an update, I took off the carb hat and filter to check the choke since that seemed easiest. My choke is completely unresponsive. I checked my other weber that needs a rebuild and that choke seems to be sprung, it always returns to a certain point, but on my 620 there is no resistance on the choke. Even moving the throttle does not close the choke, but it does slightly open it. So I closed the choke, tried to start it at 7AM... and forgot to take it out of gear. Had a nice little run to pull the key (I was standing outside of the truck starting it...)
I did go ahead and check the plugs again, all have spark. Also, compression is low, but all cylinders are very close. Highest just under 145, lowest was just over 135. I'm just glad it started first try, didn't even stumble. I do need to adjust my valves badly, haven't done it since I bought the truck in Feb of last year.
Any tips on fixing the choke? It seems like the linkage is all hooked up correctly. I'm still new to carbs so if anyone has had this issue or has any advice please let me know .