Yeah the roller that sits on the marks on the timing plate and yes it is in gear. I’ve done what I thought to be a correct link and sync but when I do it that way where the throttle cracks open in the middle of the two marks then it doesn’t reach full spark advance and is getting limited out by the throttle rod that runs all the way to the throttle upright arm.I'm not sure of some of your terms...."cam" are you talking about the roller on the carb linkage? Like Racer says, in neutral it won't allow it.
Whenever you mess with it you have to do a link and sync and there is lots of info online on how to do that.